Windows 7 will not install

Hi there guys, I have been trying for the last 3 weeks to fix this issue but no hope.

I had a boot issue on win 7 with it hanging on the boot logo, found a new problem when I boot into safe mode it hangs on "classpnp.sys" part so I bit the bullet and decide to do a fresh install on a sata 250GB seagate drive (which has had win 7 and 8 on it before now, and I did format it properly).

Now I have all the genuine software from XP Pro to Win 8, so I tried doing a fresh install on win 7 with no hope it just hanged on the "boot from CD" screen, so I tried Vista and the same thing happened, tried win 8 the same.

But when I tried XP it installed fine without any problems, so from there I upgraded from XP to 7 installed from disc drive on live desktop in XP and it half installs itself half way through the process where it needs to reboot then it stops.

It hangs on the boot logo "Starting Windows" but without the orbs.

I can get my PC to run XP but anything above that it wont install.



If anyone knows anything that i can try, I am welcome to suggestions.


Regards Grimsahw

My first re-install of 7 from 8 took a while, hangs on boot logo for ages until all updates, everything is up to date.
Make sure you have both legacy & uefi enabled (auto),
you could try install lastest drivers from option screen before letting it install 7 ?
just a thought

Check the hard drive with the manufacturer's diagnostic tools.
Hard Drive Diagnostics Tools and Utilities (Storage) - TACKtech Corp.
Hard Drive Diagnostic Procedure

Thanks Gaz, theog, I don't have the option in the bios to boot legacy etc and the bios is unchanged and fully updated as the HDD did run All windows OS for the last year and the HDD were brought from new.

Checked the drives for errors and done a full diagnostics on them but nothing came up.

For good measure I tested the ram 8GB of it for errors and viruses but resulted in being clean.

I'm now thinking it could be something else motherboard related if that could be a factor?, the machine ran fine before and before you ask I don't fix it if it's not broken lol.

Is there anything else I can do? if not I'm gonna see how far I can throw the thing.

Regards Grimshaw

Hi Ztruker, MB is now as from 12 months ago is a Nvida MB-N650-IUL9 SERIAL: 14N006155, if it helps.

No the HDD is MAXTOR 250Gb off the shelf standard drive.

Regards Grimshaw

Unplug all other HD's and peripherals,

Boot into BIOS setup, reset to defaults, save changes. If an EFI BIOS you'll need to decide if you want UEFI BIOS vs. Legacy BIOS. If UEFI follow these special steps for Install, otherwise enable Legacy BIOS or Compatibility Support Module to proceed with normal install:

Set DVD drive first to boot, HD second, set SATA controller to AHCI, Save changes and Exit.

Then boot into Windows 7 installer DVD or flash stick burned or written using tool and latest ISO for your licensed OS version here. I would use a fresh ISO written with tool in Step 2 as yours is in question.

At first installer screen Press Shift + F10, or enter System Recovery Options to open a Command Box, type:

DISKPART
LIST DISK
SELECT DISK 0 (after confirming Windows 7 target HD #)
CLEAN
CREATE PARTITION PRIMARY
FORMAT FS=NTFS LABEL="WINDOWS 7"
ACTIVE
EXIT
EXIT

Next click Install Now, then Custom install to Clean Install Windows 7 to the partition you created. If it fails then report back at which step and the verbatim error message.

In addition read over these steps to understand the tools and methods which work best to get and maintain a perfect Clean Reinstall - Factory OEM Windows 7. The steps are the same for retail.

After install you can adjust partition size or Create new partitions for data, etc. in Disk Mgmt. You are creating the partition here for the purpose of wiping the HD and marking Active which overcomes certain install failures.

Hi there Gregrocker, many thanks for the great advice but it didn't work (followed your advice to the letter).

Now I have tried installing windows 7,8 and vista on formatted new drives but only can install win XP, everything worked perfectly before now when I got "classpnp.sys" error.

So could it be anything else thats stoping win 7 and above from installing, the PC is only 3 years old, and nothing seems to have failed like the motherboard, ram, graphics card, DVD drives etc.

I'm Pc litterate, so I cant see what is the isuue?.

Regards Grimshaw

Confirm you have all other HD's and peripherals unplugged during the Win7 install attempt, and that you followed the other above steps exactly.

Confirm that you didn't install XP first to do an Upgrade which is completely unnecessary.

The reason I ask is if you have an Upgrade version key and truly wiped the HD then it should reject the key during install, requiring you to leave it blank and then afterwards do the quick Option 2 workaround in Clean Install with a Upgrade Windows 7 Version.

If you did all of these steps, then where did you get the installer?

Test the HD and RAM with bootable disks provided from Troubleshooting Steps for Windows 7

Hi Gregrocker,

Yeah I have checked all my HDDs for errors but they came out clean also the RAM showed no errors.

I have even purchased a NEW HDD and tried installing that way but still no good

All my software is OEM and Retail 32bit and 64bit versions of MS windows OS, I have tried them all with no success, the only thing that installs is XP but I cant upgrade from there either because it hangs trying to upgrade to win 7 or vista permanently after reboot.

I am thinking it could be something in the bios that needs altering (Pheonix Bios) or maybe the motherboard perhaps, also I have shorted the CMOS.

The reason I am persisting with this, is because it was my mothers PC that I had built for her a few years ago and now it's in my possession, sadly she is no longer with us.
So I am keen to get this sorted :)