I don't know, this doesn't sound like an OS problem to me. It sounds like something is getting messed with hardware. You could try this to cut your list of potential perpetrators in half:
Load your computer with a Linux Live boot disk or Bart's PE. If your computer still acts weird you know its hardware. If not, then its software or perhaps your harddrive (since you're using a boot disk).
If its hardware, you can remove components done to the minimum, reseat cards/ram, dust it out and try to isolate components.
If its software, you can try updates, different drivers, system restore points, etc. Any other suggestions anyone?
p.s., you can always reinstall windows if you boot off the Windows disk. You can reformat your harddrive once the installer is loaded.
"To err is human - and to blame it on a computer is even more so." - Robert Orben