Computer Issues IV

Well, no longer do I think it's a virus, but now I have no clue what's wrong with my computer.

Let me explain. Last night I reformatted both of my computer's internal hard drives and left the external hard drive turned off and unplugged from the computer. I reinstalled Windows XP on the main hard drive but got the blue screen of death halfway through so the installation restarted. The second installation worked fine, and Windows loaded and activated over the internet and everything seemed fine.

So I started downloading updates, and my anti-spyware programs I use, and Firefox but a lot of programs when I tried to install them said that they were corrupt. So then I figured out that I should update the Windows Installer to 3.1, so I downloaded that and installed it. But I was still having issues with installing stuff because files are corrupt or missing. I couldn't even install my sound driver, cause it said that was corrupt! And I tried to install my nvidia geforce driver from the CD, but then I had to remove it from startup because it kept on crashing the computer. And the one I downloaded from the website didn't work.

I was able to install Firefox, but every time I tried to run it the error message came up that said a serious error has crashed Firefox. I managed to update Internet Explorer to IE7, and that sorta works. Everytime I visited Facebook the browser would crash. The computer just kept on crashing and restarting! And it can't be a virus, cause I did reformat both internal drives. What kind of virus would that be? Maybe's it a hardware issue....I need to get the motherboard checked out.

I tried to install Service Pack 3 but it failed halfway through, and then Windows wouldn't load at all the next time the computer restarted. So I'm using the disks to try to repair the existing Windows installation. I didn't know it had to go all through the process of installing again though, I thought it would just replace a couple of files! At this point I must have installed Windows about 20 times, it's a wonder I don't know the key code by heart!

Anyways, I read a post in a support forum that said maybe Windows Firewall is corrupting the installation files, so I'm going to go home and turn that off and see whether that helps. I would like to be able to install my anti-virus software and run a scan. Wish me luck!