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Windows 7: Clean Reinstall - Factory OEM Windows 7

Clean Reinstall - Factory OEM Windows 7

How to Clean Install an OEM Windows 7
Published by gregrocker
15 Mar 2012
Published by

How to Clean Install an OEM Windows 7

information   Information
A clean reinstall is often better than getting a new computer since most PC's come larded with sponsors' bloatware and duplicate utilities that interfere with much better versions built into Windows 7. For this reason most tech enthusiasts clean reinstall using the Product Key on the COA sticker affixed to machine. This guide compiles everything that works best in tens of thousands of installs we've directly helped with here.
warning   Warning
Please read over all steps to be sure you understand them before beginning. Ask back any questions in the Comments section below. For example, it is important enough to understand exactly how drivers are handled in the first mostly driver-complete OS that these steps are printed in red.


Step 1
Find the right Windows 7 .iso

If needed download the latest official Win7 OS installer ISO file with SP1 and Media Refresh for your 32-bit or 64-bit licensed Windows version. If your version is unavailable, download another version to unlock all versions with eicfg removal tool.

You can slipstream the latest Updates into the installer ISO to save at least an hour's Updating after install using Update 7 installation media. However it may take an hour to do this so consider how much you want this.

If the licensed OS printed on the COA sticker on bottom is Home Basic or Starter then download Home Premium, run the eicfg removal tool to unlock all versions, later during install choose the licensed version from menu.

Burn ISO to DVD or write to USB flash stick (minimum size of 4GB required) using Windows 7 USB-DVD Download Tool.

Step 2
Backup your user data

Back up your files externally by copying your named User account or active User folders to another HD, external drive, flash stick or disk. Don't forget to export your browser bookmarks first. ▶ Copying files to an external drive - YouTube

If your email is stored on computer, Google how to back up specific mail and account settings to get solutions like How do I import and export email, contacts, and calendars with Windows Live Mail? - Microsoft Windows Help.

Backup Quickbooks 2010+ Company files from User/Public/Documents, google your version's file location, or run a QB backup, De-authorize I-Tunes.

For unbootable Windows copy data to another HD or USB device using the Windows 7 disk to Copy & Paste - in Windows Recovery Console, free Paragon rescue disk or a Linux boot disk.

Run and print an audit of hardware and software including installed Product Keys using Belarc Advisor. This audit assures you won't lose any other paid software keys like Office. Note that the Windows 7 Product Key found by Belarc or another key finder will be an SLP batch key used at factory, if it has not yet been activated from COA sticker key used for a Clean Reinstall. This SLP batch key cannot be used for reinstall.

Step 3
Save essential system data

If you have a Recovery partition it may not run after clean reinstall. You may want to make your Recovery Disks so you have a path back to factory condition, following the steps given in your PC's setup literature or in the Manual located on the Support Downloads webpage for your model computer. As an alternative to Recovery Disks you can save a Windows 7 Backup Image or Macrium Image of the entire HD.

You can wait until afterwards to see if Recovery or (Diagnostics) Tools partitions will run from boot to decide if you want to delete those partitions and recover the space into C or elsewhere (using Step 3 here).

Step 4
Find the product key for activation

Write down the Product Key from COA sticker located on back or side of PC tower, bottom or under battery of notebook. Make sure you get the characters correct as this is a main cause of activation failure. You can input or Skip the key during install then afterwards activate at Control Panel>System, which may require a quick robocall. But put the key in a safe place so you have it for the life of the PC, which may outlast the sticker's readability.

The COA sticker looks like this:

Name:  coa-stickers.gif
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Size:  495.9 KB

Step 5
Manage installed programs

Gather your program installers. For those lacking disks, you may find them on the program's Support Downloads webpage. Favorite pre-installed apps may be found on the Downloads webpage for your model computer or manufacturer-provided Apps Disk. Others may be found by googling. Some pre-installed apps may not be available for clean reinstall - more about this for your brand PC in Step 13 below.

Many of the favorite apps needed and desired for reinstall are available in the terrific app Ninite - Install or Update Multiple Apps at Once.

Just in case, save in advance your Wireless or Ethernet LAN (wired) driver in your backup so if it isn't provided during install you can install it to get online quickly. These can be found on the Support Downloads webpage for your model PC. The exact make/model will be listed in your Device Manager under Network Adapters.

Step 6
Install the Windows 7 .iso

Unplug all other HD's and peripherals except ethernet cable to increase chances of it starting up connected after install. If not prompted for wireless key during install it's likely you'll need to install the wireless driver immediately after getting to the desktop.

Boot the Windows 7 installer, choose Custom Install, then at the Drive Selection screen access the Drive Options (Advanced) to Delete all partitions not needed, repartition and format as shown in Steps 7 and 8 of Clean Install Windows 7 - these illustrated steps will guide you through actual install.

Whether to use more than one partition depends largely if you want your data in the OS partition, or have it linked from another partition to make C partition backup image smaller - this way if Windows 7 becomes irreparable you can re-image the OS/Programs to C and the data will be current and waiting in its own partition.

If you don't want to keep any partitions but also don't have a new partition scheme in mind, then use the Drive Options to Delete all partitions, click Next to let the installer create and format your installation partition for you. Ignore the small boot partition which is created.

Until Windows 7 installer is updated with USB3 drivers use a USB2 port for flash install. If you're prompted for drivers for any other reason during install it almost always means a bad installer, so make sure ISO download completed and create another one.

If you have an EFI BIOS, or receive an error that Win7 cannot be installed to this disk because of its formatting, and cannot overcome the error by deleting all partitions, then you may need to follow the special steps to Install Windows 7 with UEFI (Unified Extensible Firmware Interface) including Create UEFI Bootable USB Flash Drive - or to Bypass UEFI to Install WIn7.

Other Steps here to Troubleshoot Windows 7 Installation Failures - Windows 7 Help Forums

Step 7
Get online to run all Windows Updates

Immediately after install check bottom right System Tray network icon to connect to your network if necessary. If only a TV icon with a red slash appears then open and extract network LAN driver, right click on Setup to Run as Administrator, install LAN driver watching System tray icon to choose network if required. Why can't I connect to a network? - Windows Help

Immediately after getting online install your AV. I suggest using a lightweight free Antivirus like Microsoft Security Essentials or the more aggressive Panda Cloud which work perfectly with the Windows 7 Firewall.

Then enable hardware driver auto-updating, open Windows Update to Check for Updates, select all Important and Optional Updates (except Bing, unless you prefer it) to install. After requested reboots, go back again to Check for Updates until there are no more. These Updates deliver drivers, critical system, hardware and security patches. I would accept them all to be safest, keep Updates set to Automatic and regularly check for Optional to install.

If Updates stall or balk check your Start menu's Shutdown button for a "!" signaling there are Updates queued there for install at Shutdown. Perform a Shutdown to install them and then keep an eye on the Shutdown button if further rounds of Updates stall to clear them there first before proceeding to Check for more Updates.

Any drivers still missing in Device Manager after all Updates are installed can be found on the Support Downloads webpage for the model PC or device, along with other OEM software - which you can wait to see if you need.

I would not replace any drivers given by the installer or Windows Update unless performance problems point to that specific driver. We can help you troubleshoot these issues. If you install a driver and it performs badly you can Roll Back on its Driver tab in Device Manager.

"Standard VGA" Display driver is a placeholder driver which only should be used when no other possible driver will install. So if Updates doesn't provide a better driver import it from the model's Support Downloads webpage -
if necessary even Vista or XP driver installed in Compatibility Mode.

Unknown Devices are often card readers, or may be revealed by a function still missing on the PC such as laptop function keys or keyboard lighting, or can be traced using Device Manager - Finding Unknown Devices - Windows 7 Help Forums

Co-processor, SM Bus controller, USB and Storage controllers are often elements of the chipset. If no chipset is posted on your model's Downloads page, ask in our Drivers forum. You can also trace any missing driver using Hardware Identification. It's often faster to google the Driver Detail's Hardware ID shown than look it up.

I would not re-import any of the OEM software until you run for awhile to know for sure you need it. There may be patches on the Support Downloads webpage needed to improve performance so browse them to be aware what's available as you test performance to see if they're needed. But keep in mind re-installing OEM bloatware besides that which is absolutely needed for good performance or a specific function you need defeats the purpose of a Clean Reinstall.

Step 8
Reinstall your programs

Install programs slowly over time to gauge performance changes after each. You can roll back bad effects of a Program install or Update(s) by uninstalling it or using System Restore.

Install the latest Adobe Reader and Flash Player from Adobe - Downloads. I no longer recommend installing Java unless you know you need it or are prompted to install it to run a program, as it is an infection path.

Don't let any programs write themselves into msconfig>Startup as they slow startup, become freeloaders on your RAM/CPU, can spy on you and cause conflicts. No video, sound or other driver software needs to start with Windows 7.

As illustrated in Startup Programs - Change uncheck everything except AV, gadgets (aka "Sidebar"), Sync program, and Flash player updater (needed for safety and performance) in msconfig>Startup.

Then after reboots do the same in msconfig>Services after checking the box to "Hide All MS Services."

Check back with both lists periodically to see if anything writes itself back in, turn it off in its Program Preferences.

If you have any questions about a listing, Google it to learn what it does.

However I would not install any Google programs which are relentless spyware. Only use the stable Google search box in your browser and don't stay signed into any Google web apps.

Avoid spyware tracking cookies placing annoying interest ads by periodically Opting Out of Network Advertising. This will greatly relieve the banner ads which track your shopping habits.

The most important thing you can do to avoid spyware creeping in is to watch your program installs like a hawk at every step, because freeware authors have found ingenious ways to sneak in spyware with tricky check box choices - even in the License Agreement. I always do a Custom install and only allow the features I know I want, later removing anything extra in Control Panel>Programs and by running a full Malwarebytes and SuperAntiSpyware scan (Step 12) which roots them out as deep as they can go.

Keep an eye also on your Browser Add-Ons or Extensions to only allow the ones you know you want or are required to make a page display correctly, including Flash, Shockwave, WMP or Quicktime plug-in, a reader, Silverlight. Also under Add-Ons Monitor Search services to only allow Google in the stable browser search box, disallow any others to replace it.

If you're prone to infection add the inexpensive paid real-time protection for Malwarebytes to run alongside your AV, otherwise use its excellent free scanner as needed.

Step 9
Recover your user files

Before copying your files into the new install, now would be a good time to download, install (declining trial), update and run a scan on them with Malwarebytes to make sure no infection is being reimported.

To copy your files into the new install, open the storage folder, open each User folder (Documents, Pictures, etc.), from the Organize tab Select All, then drag the group to the corresponding folder on Explorer bar at left. Wait until the bar stops unfolding and hypertext confirms the precise copy location before releasing the left click. Do not copy hidden AppData folders from User Accounts as these are a corruption path- another reason not to use file transfer apps which can lose files.

If you're using a separate data partition copy your User folders to it, then you can either move the new install's active User folders following User Folders - Change Default Location*, or right click each to link it to the related Library - Include a Folder then set it as default for that Library - Set Save Folder - Windows 7 Help Forums. Keep the empty C User folder in each library so you can easily see if something lands there and simply drag it to the linked User folder. *If you move the User folders use another Backup Imaging app as the built-in one will want to include the data drive which now holds System files.

A simple free method is here to Sync, Backup and Store your Files to the Cloud with Onedrive - Windows 7 Help Forums that shows how to move your User folders into OneDrive folder on C or data partition for instant backup to the cloud and simultaneous synching across all of your devices using this method.

Step 10
Recover your bookmarks

The User Favorites folder will populate IE Bookmarks. Import another browser's Bookmarks from HTML file backed up previously. Copy Quickbooks and other Program data into it's default folder location.

Step 11
Activate the OS

Activation at Control Panel>System may require a robocall to MS the first time to record your hardware signature in their servers. It will always work as long as you install the correct version and input the key accurately.

Step 12

You can easily configure and share files between PC's on the same network using Homegroup - Create.

On my installs users are most impressed by the spectacular beauty of the collected national editions' 120 Windows 7 Backgrounds slideshow. You can download the folder from Type Personalize in Start search box, choose Windows 7 Aero Theme, from Slide Show link Browse to Pictures Location, Select folder, Select All as a 30 minute random slideshow, Save Changes.

With gadgets no longer being supported what works better now for millions who love them is to install v.12 or higher of 8GadgetPack - Gadgets for Windows 8 / 8.1 which supports Windows 7.

When finished, clean and order the HD perfectly using state-of-the-art free CCleaner "Run Cleaner" button and Registry tab.

Type "Defrag" into Start Search box to run a Windows defrag and set its schedule to your liking. I use and highly recommend Puran free boot-time defragger + Full Disk Check (after checking Intelligent Optimizer on Additional Operations tab) for state-of-the-art defrag which includes System files that are inaccessible because they're running in a Windows defrag. Never defrag an SSD!

Periodically run the above as well as a full scan with free Malwarebytes and SUPERAntiSpyware on-demand scanners, declining the trial unless you're prone to infection - in which case purchasing MBAM Real Time protection at $29 for life almost always resolves this, when run in tandem with your AV. Always check that you are running the latest version of the scanner and it is fully updated.

Take advantage of the perfected Windows 7 Power Options. Most users only need the Balanced Plan, ideally to Sleep at 30, Hibernate at 45-90, with Hybrid Sleep enabled. Many users prefer Hibernate to Shut Down as it keeps in place your open work and starts up much faster while still powering down. Note that timing out to Sleep without a Hibernate safety net will wear your RAM indefinitely until you come back (vacation? ).
Sleep and hibernation: frequently asked questions
Hibernate Shortcut - Create

Step 13
Make your first system image

Finally, save a Windows 7 Backup image to external or another internal HD so you never have to reinstall again - just do a System Image Recovery to the HD or it's replacement from booted DVD/Repair CD and the stored image.

Note that built-in Win7 backup imaging is limited to restoring the OS to the exact same partition structure, so if you want a more flexible app try recommended Macrium Imaging - Windows 7 Help Forums .

Step 14
Some other considerations

Henceforth if required to contact your OEM Tech Support do not tell them you Clean Reinstalled but troubleshoot as if you have the factory install. Otherwise they may refuse to support Clean Reinstall, but cannot void Hardware warranty. If you must ship the unit back for repair under Hardware warranty save a Windows 7 backup image and then run Factory Recovery beforehand.

After reinstall I always scan the logs to resolve repeat errors, check System Resources, search for Problem solutions, Generate a System Health Report - as shown in these basic Troubleshooting Steps for Windows 7 to bookmark.

Step 15
Notes for specific PC makes

Special notes for HP owners:

On newer models HP System Recovery may offer a Minimized OS Recovery option. This retains only the OS, Recovery Manager, HP Support Asst, HP Wireless LAN, drivers and activation, and is as close to a clean reinstall as you can get without doing one yourself. I would uninstall HP Wireless to use Win7's superior wireless manager.

If you format and reinstall only to C leaving all other partitions intact, F11 Recovery key should still work later if you need it. The helpful hardware diagnostics also listed on the ESC or F9 boot menu may also run after reinstall, so if they will run now from boot, I would save the small HP Tools partition to see if they remain bootable after install.

Problems with volume control lighting and HP Quick Launch buttons have been dealt with here and here.

Specific HP software which might be worth reimporting is discussed in HP Bloatware, or useful system utilities?

Some HP Recovery disks can have their files extracted to access favorite program installers using Accessing HP Recovery Disc Files.

Special notes for Dell owners:

If your Recovery partition is triggered at boot from the F8 System Recovery Options then it will no longer run after clean reinstall, so make your Recovery disks first, delete Recovery partition during reinstall.

The bootable Dell Diagnostics often will run after Reinstall so are worth saving if they will boot. Try it now to test your hardware and see if these work, choosing on F12 menu Diagnostics and then Utility Partition which sometimes has a fuller suite. If they run save the Dell Utility partition during install, if not delete all partitions. These tests can also be run online at Dell PC Diagnostics | Dell US

Useful tips for Dell re-installation plus access to their forums to resolve questions can be found at Dell Community . The Dell Reinstallation DVD has only activation and a Dell logo added and can be used as long as it is labeled to include SP1.

Special Note for Sony Vaio Owners:

Software which enables F-key functions and illumination must be reinstalled from the Sony Support Downloads webpage in the order as shown here: Function keys don't work after clean install - Windows 7 Forums

Special Note for Samsung Owners:

Software which enables F-key functions and illumination may be labeled Easy Display Manager.

Special Note to Acer Owners

There is an OEM Preload folder in the C:/ drive that holds all the pre-loaded software, including the eRecovery software.

Special Note for Lenovo Owners

The only OEM software I've found to be valuable is Power Management's features to preserve battery by maintaining a lesser charge when plugged in, and fan reversal to clean out dust. Download from your model's Support Downloads webpage or Power Manager for Windows 7 (32-bit, 64-bit), Vista (32-bit, 64-bit) - Notebook

Special thanks to Wolfgang (whs) for helping to reorganize this tutorial after 1 million views and the many contributions users felt important enough to include.

Office Word version: How to Clean Install an OEM Windows 7.docx

15 Mar 2012   #1

Microsoft Community Contributor Award Recipient

Windows 8.1 Pro with Media Center

Well done, Greg. A great tut on an important matter.



My System SpecsSystem Spec
15 Mar 2012   #2
Microsoft MVP

Vista, Windows7, Mint Mate, Zorin, Windows 8

Great, I kept wondering when you are going to put it together.
My System SpecsSystem Spec
15 Mar 2012   #3

Microsoft Community Contributor Award Recipient

Windows 7 Ult. x64

You finally did it! Great work Greg - welcome to tut-world.
My System SpecsSystem Spec
15 Mar 2012   #4
Microsoft MVP


Thanks, guys. Had been using a post I've linked countless times because I thought that it is more a compendium of other tutorials than one of my own.

But Shawn said it qualifies so here it is.
My System SpecsSystem Spec
17 Apr 2012   #5

Windows 7 Home Premium x64

Absolutely fantastic tutorial thread. I have successfully clean reinstalled Windows 7 Home Premium to my new Acer laptop.

A sincere thank you to gregrocker for posting this.

I do have one question. When I resintalled, I formatted the primary partition and reinstalled without a hitch. However, I did notice two smaller partitions that I am assuming hold the hidden factory backup? Do I need these or may I also format them and backup the new clean ISO to them? I am also creating DVD backups off the new clean ISO.
My System SpecsSystem Spec
17 Apr 2012   #6
Microsoft MVP


Hi Rocketsfan -

Can you post back a screenshot of your maximized Disk Management drive map, using the Snipping Tool in Start Menu? Disk Management - Post a Screen Capture Image

On Acer it's unlikely Factory Recovery or any OEM partition is still functional or needed, so as dealt with in the tutorial I would consider deleting them.

You can now recover the space using Disk Management to Delete and Extend C to the right, or free Partition Wizard bootable CD to Resize C to the left.
My System SpecsSystem Spec
17 Apr 2012   #7

Windows 7 Home Premium x64

Here is my Disk Management drive map. Your help and advice is greatly appreciated!


My System SpecsSystem Spec
17 Apr 2012   #8
Microsoft MVP


Did you keep the Recovery partition to see if it will still run after Clean Reinstall?
You can wait until afterwards to see if Recovery or Tools will run from boot to decide if you want to delete those partitions and recover the space into C or elsewhere.
If so then test using it's hotkey at boot as given here: Acer Support: Restoring a system to factory load.

If it will cue up then you can keep it, but if it's lost ability to boot then you can either leave it or recover the space using free Partition Wizard bootable CD: boot CD, rightclick Recovery to Delete, click OK. rightclick System Reserved to Resize, left click grab the partition and slide it intact all the way to the left side of HD, click OK. Then rightlclick C to Resize, slide left border all the way to the left, click OK, Apply all steps.

It may require repair using Rebuild MBR from PW Disk tab when you Resize on the boot sector. I hardly think it's worth the 16gb unless you want to play with it. Back up your files.
My System SpecsSystem Spec
17 Apr 2012   #9

Windows 7 Home Premium x64

Quote   Quote: Originally Posted by gregrocker View Post
Did you keep the Recovery partition to see if it will still run after Clean Reinstall?
You can wait until afterwards to see if Recovery or Tools will run from boot to decide if you want to delete those partitions and recover the space into C or elsewhere.
If so then test using it's hotkey at boot as given here: Acer Support: Restoring a system to factory load.

If it will cue up then you can keep it, but if it's lost ability to boot then you can either leave it or recover the space using free Partition Wizard bootable CD: boot CD, rightclick Recovery to Delete, click OK. rightclick System Reserved to Resize, left click grab the partition and slide it intact all the way to the left side of HD, click OK. Then rightlclick C to Resize, slide left border all the way to the left, click OK, Apply all steps.

It may require repair using Rebuild MBR from PW Disk tab when you Resize on the boot sector. I hardly think it's worth the 16gb unless you want to play with it. Back up your files.
I have a factory backup on discs so I'm not too concerned with having the factory backup on the hidden partition. Can the new clean install be backed up to that partition?

As long as it's not going to interfere with Windows normal operating procedure or a possible future recovery if something goes wrong, I'm almost inclined to leave it alone.
My System SpecsSystem Spec

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