Bad RAM is a common source for file corruption errors. It could also explain some of the other things.
First thing is to make sure you're actually formatting, and not just installing over top. If you don't see some progress indicator that says something like "Formatting", you didn't format the drive, so something from the old install could potentially be causing problems for the new one.
Assuming you've done that, one important thing to do with a new XP install, is make sure a firewall is installed and running before you ever connect it to the Internet. Go to some other system, which you are reasonable sure is clean, and download a copy of ZoneAlarm or something, and even the 130 odd MB SP2 installer. I say do this on another system, because if you DO have a virus or something, it could reinfect your system by installing itself onto a floppy, CD, or USB thumb drive.
Be sure to install BOTH of these before you ever connect to the Internet. You may even want to consider creating an install disc with SP2 slipstreamed in. Dialup or some kind of broadband, yank the cable connecting you to the outside world until those things are done. Then the first thing you want to do is hit the Windows Update site. Don't go ANYWHERE else until all updates have been installed. This may take 2-3 sessions, rebooting between, so have a book or something handy if you need entertainment.
Once you've done all that, here are some tips you can use to avoid problems in the future. They are only suggestions, but the more of them you follow, the better off you'll be.
1: Do not use Internet Explorer
1a: Replace it with your choice of Mozilla Firefox, Opera, Safari, or Seamonkey
2: Always install Windows security updates
2a: The lone exception to rule #1
2b: They're typically released every second Tuesday of the month
3: You should have some kind of firewall
3a: XP/Vista's firewall is good enough, routers are better, and third party firewalls are also viable options
4: Be sure to have an Anti-Virus program
4a: You can get AVG Free and Avast for free if money is an issue
5: Avoid pirated programs
6: Avoid file sharing (P2P) programs
7: Avoid using Outlook/Outlook Express
7a: Virtually any email program is safer, web email can be even better
Hi, I'm stuck and need help badly. My PC has something drastically wrong with it, that i'm putting down to being a virus. A little while ago i noticed my PC (which is only 4 months old) started to become unstable and would crash often. Then i noticed AVG had stopped working. After reinstalling the software, it ran fine, however after updating all the virus signitures it suddenly became unable to access any of the drives, therefore not able to complete a scan. It would either just hang or report an error saying it couldn't access the drives. I tried to install other virus scan software with the same result. The program would either hang or just shutdown the PC. Other programs would come up with a file corrupted or destroyed error.
Towards the end of my tether i descided to reformat my drive and try a fresh instal. Instal went fine, could not install all windows security updates. Service pack 2 kept coming up with corrupt file error, and i was back to system crashes every time i tried to scan. So i reformat again. Network connection removed, i install a new Antivirus program (Bit defender). I also install AVG and update to latest signitures. Same problems occour. AVG can't access the drives and Bit defender can't connect to it's virus scanner. What gives? I've tried scanning with Chkdisk for bad sectors or hd problems but thats fine. I have also tried to run various online scans which just hang and do nothing or just won't start at all. It's like what ever move i make is blocked. Any ideas of what i should do? I figured the reformat would kill everyhting but it appears i was wrong.