Can't re-install Windows 7 (Factory Install) after virus

My Acer 7736Z-4809 laptop (pre-installed w/ Win7 Home Premium 64bit, so I don't have the Win7 CD) was recently hit with a virus. I constantly got the BSOD "iaStor.sys" and a black screen. Startup Repair at first couldn't complete repair, but when I tried again, it found no errors. Tried System Restore to no avail. Was able to do a System Image Recovery using a backup on an external HD, but none of the programs worked (wanted to use Ad-Aware and Spybot to eliminate the virus). When I clicked on programs on the desktop or Start menu, nothing happened, didn't even get an "Open with." Even in Safe Mode, none of the programs worked. I checked the Task Mgr, and explorer.exe was still there, but RAID wasn't. Went to Control Panel Programs to uninstall/repair programs, but got message that programs seemed to be already uninstalled...it was like the programs weren't even recognized. Once in awhile when I clicked on IE8 in Windows Explorer (not via desktop shortcut or Start menu), IE8 actually opened, so I downloaded Hijack This and Avast anti-virus, but when I tried to install them, I got the msg: "Installation must be on a local hard drive."

Continued to get the "iaStor.sys" BSOD. I read to run Verifier and disable it, so I tried that (not sure if that made things worse). Tried to do another System Image Recovery, but this time it couldn't recognize the backup on the ext HD. Tried Startup Repair, and it couldn't complete repair. Went to Recovery Management to reset the OS, but my User ID(?) couldn't be found. Decided to do a Factory Install - during "Setup is preparing your computer for first use" I got the error msg: "The computer restarted unexpectedly or encountered an unexpected error. Windows installation cannot proceed. To install Windows, click 'OK' to restart the computer, and then restart the installation." Every time I try to restart it, I get the same error msg.

BIOS Setup Defaults:

Quiet Boot: [Enabled]
Network Boot: [Enabled]
F12 Boot Menu: [Disabled]
D2D Recovery: [Enabled]
SATA Mode: [AHCI]

Thanks in advance.

With the verifier enabled you'll be getting BSOD's non-stop, must disable it ASAP.

Glad to know I didn't do further damage when I disabled it. Thanks.

You can get your product key from the system if you can logon (for example use SIW in our freeware database and look in the product keys section) or it may be on a sticker on your computer. You should write this number down somewhere safe.

Then you can download and burn the Home Premium 64 DVD and reinstall fresh if you like.
Please read the NOTES regarding the difference between OEM W7 & Microsoft's official ISO.

Thanks, I found the product key sticker on the bottom of the laptop and wrote down the number.

I tried to download Win7 HPx64. The ISO is supposed to be 3GB, but mine turned out to be only 1.2GB even though the download was complete. I think the problem is that this laptop I'm using now is very old. Anyway, I ordered the recovery disc(s) from Acer - will one of these discs have Win7 HPx64? The Acer site doesn't state what's on the disc(s).

It should include their OEM W7 to restore the OS files.

The age of your computer should have no bearing on whether downloads complete properly. It's a browser and a file. If you have HD space and the download runs properly then when it finishes you should have the file. Did you check the file to see if it was valid? (Not that it matters, of course, because you have the manufacturers disk on the way)

Thanks.

I downloaded the ISO again with the old laptop, and the result was only 1.4GB. I got the Low Disk Space warning of 1MB remaining on the C drive even though I downloaded the file to an external HD, which has more than enough space. Why is that? Is the file being temporarily saved to the C drive? When I started downloading, the C drive was showing 1.5GB of space, and that dwindled down to 1MB as if the file was being downloaded to it.

The old laptop I currently have to use is nearly 10 years old, and the C drive has a capacity of about 7GB. It also only has 128MB RAM, and the processor is 492 MHz. These specs are all OEM. That's why I bought the Acer laptop, which is about 14 months old now.

Yes downloads are copied to the browsers temporary folder (even under a temporary name I believe) until they finish, then they are copied and named when complete.

Is there a way to disable copying to IE's temp folder? There isn't 1.5GB of programs left or any other stuff on the C drive that I can uninstall/delete to clear up more space.

Not that I am aware of, but you can move the temporary folder and then move it back.

Tools ... Internet Options ... General Tab
Settings
Move folder