Bad memory sticks can easily cause memory corruptions (if you’re an overclocker you’ve probably seen it before)
Try running memtest (just to make sure)
Download Driver Checker
i know it seems like some commercial shit that doesn’t work, but trust me, it does. it is very easy to install/deinstall drivers 
oh, and you’ll have to torrent it or buy it 
EDIT: bleh, didnt read the whole thread, this probably doesn’t work if reformatting didn’t. but driver checker is still a great program :3
Clean the gunk out of the mouse.
HI,
I think so that the problem might be with the the system, As the system is too slowed down. When you start the PC when it start just go to the run command and then type “msconfig”, In the msconfig panel disable all the startup as well as disable all Non-Microsoft services and restart the PC. These will solve your problem, but you still need to remove all the unwanted softwares from your PC and clear all the temp as well as unused file. These will really speed up your computer as the new one.
I must say I am really dissapoint at all the useless static in this thread. If you are not gonna help the guy out, then just shut ur trap! sheesh!
Anyway, I would say it is a hardware thing but I know very little about hardware.
I don’t know how much help this is seeing how you’ve already done a format (meaning all your data is gone), but try going into the BIOS and resetting it to factory settings (usually F5 to load defaults and F10 to save and exit, but this might vary). Then boot from a Linux (Ubuntu) live CD to see if this works.
If the live CD works then you might be able to see what the problem is from within Linux, and maybe use MemTest (it’s on the disk) to check your memory.
Also, if you manage to get into Linux from the live CD, feel the fans on your PC to see if they’re running hotter than usual.