Woops Can't install Win7 now

ACER 3920, i3 processor, 1TB, DVD, 4MBs DDR3 was running Win7Pro
Woops..it looks like I have completely cocked up my hard drive.
The shop partitioned and put a hooky Win7 Ultimate on. I changed it using an Upgrade Professional disc, a Microsoft Partner disc. It ran fine for weeks then crashed once, I couldn’t find a virus so decided to reinstall. I formatted the D: Drive before attempting to reinstall to the C:
I went to reinstall and did a delete on the 100GB drive, I think that was wrong. After that it said I couldn’t install to any drive.
After that I put in my ultimate disc, full not upgrade, and the partitions changed I got an extra one with 100MB and System, I then stopped the installation..an error now I think. I then put in the Professional disc (an upgrade)...it said CD/DVD Drivers missing, but I couldn’t get the disc out to see if putting in the ACER driver disc would sort it, so I switched off.
So I intended to try and put the ACER drivers onto a usb and the go back and try the Ultimate disc and let it install along with the drivers. Afterwards do the registry change and install the Professional disc.
However on starting I now get the dreaded ‘bootmanager is missing’ do Control Alt Delete. This occurs almost straight away when I attempt to re-install anything.
So I have no idea what to do. I have read that I may be able to install from of a USB. What I want to eventually do is to completely wash the drive and remove the partition then do a re-install with my Win7 professional.
As you can tell I’m not exactly up on computers. What could be a way forward please.
Please no..you are a whatever....I know

I think I would start over, delete all partitions, create the partitions you want and when windows creates the 100 Mb system partition, leave it alone. Its only 100 megabytes and contains recovery tools etc. Windows will likely prompt you to tell you its going to create it. You won't see it unless you go into disk management and it won't affect your drive letters.

I agree with alphanumeric's advice.

Just boot from your Windows DVD and go for the Custom install. Windows 7 will indeed create a 100MB partition to hold the boot files, but you'll still be able to create another three primary partitions should you need them, and it is better to do it at this stage, because you can decide exactly what the partition sizes are going to be.

Windows 7's Disk Management utility is not very versatile, and for that reason, many people use third-party disk management software such as Macrium, Acronis and Paragon etc..

Try a full clean & full format in command prompt.
SSD / HDD : Optimize for Windows Reinstallation

If you wipe the HD then you'll need to leave Product Key blank, after install do a workaround to activate Upgrade version on a clean HD: Clean Install with a Upgrade Windows 7 Version

Try this first: Put the Professional DVD in the drive, restart to boot DVD, choose Custom Install, use Drive options to delete all partitions, create new ones as you wish, accept and leave alone the 100mb boot partition which places your Repair console on the F8 Advanced Boot Options.

Install to the first partition after 100mb.

Follow the rest of these steps to get a perfect reinstall: Reinstalling Windows 7

Thanks Guys.
Well with a little help, I installed Win7 Professional (upgrade) from a bootable USB, it all went in OK. I think my error was not booting the CD from bios, used F8 instead of F12. Rightly or wrongly I opted for just a C: Drive.

I now know how to change if necessary.

I still have a problem in when I installed the driver for HD6450 straight from the ACER web site it just didn’t work after that, eventually the mouse pointer appeared but the screen stayed blank.
As it was working fine before HD6450 driver installation I think that there is a problem and will call ACER tomorrow as I have a 1year onsite warranty.
The driver that I installed was (if anyone wants to check...Home | Acer and it’s an ACER Aspire M3920) You go Support...Drivers and Downloads...then it’s in Thai but the third writing down...then ASPIRE, then M3920.....thanks
VGA
AMD
VGA Driver (HD6450)
8.830.0.0000

141.6 MB

2011/05/06


So the graphics specified for this computer is ATI Radeon HD6450 1GB dedicated Graphics Memory (DDR3) Microsoft Direct X 11...whatever that is... I’m fairly sure that it was the correct driver.
I have learnt a lot by reading on this site........................thanks

On this Acer site HD6450 & a HD6450M are listed, are you downloading the right drivers.

Acer Support: Downloads & Support Documents - Desktop / Aspire / Aspire M3920



Have you download the Acer updater.
http://global-download.gateway.com/F...rDetection.exe

On both Acer sites HD6450 & a HD6450M are listed, are you downloading the right drivers.

The Display driver is left off the list because it is either in the installer or via optional Windows Updates: Automatically get recommended drivers and updates for your hardware

Win7 drivers are automated. Use the drivers given by the installer or quickly updated via optional WUD.

If this is not sufficient, go to the AMD Support Downloads drivers webpage to browse for your model.