Need computer genius...

[Kamintar]

Ok guys here's the deal....

Last night, computer was working fine, no issues whatsoever. I turned it off, and then when I turned it on this morning, something was freaking out. My Ad-Watch said like 300+ registries were changed (Before I closed it), and now, nothing works.

I can't even open up a program that came with the computer. The only thing I can really do is look at my files, move them around, but I can't open them. ALL of my files (for the most part) have the little icon that says it can't open it (and then when you click on them it gives you the "Pick program from list..." or "Search internet for program" crap). Every single program I have seems to not be working, except for a few things like iTunes or Winamp (because my files for those still show the correct icons).

Here's the catch...I didn't do anything different last night. I haven't done anything to my computer in like 2 months. I didn't download anything, I didn't install anything, and it just seems to have crapped out.

All my files still have the correct extensions, but I just can't open them.

Running WinXP Pro (2001 I think), got a relatively new MoBo and Processor, 1GB of RAM. I don't know what could be causing this problem. The only solution I see is to reformat my computer. And I hate doing that, especially when I'm 5% from dinging...

Any sugestions?