"_appcompat.txt" - Can't access web browsing, at all.

Hello TSF,
This is my first post and I must say I am sure glad I found a general, have it all, tech support site for use in the future as well.

Yesterday morning all was well when I was on my computer, browsing the net-doing nothing out of the norm. When I got home, the net wasn't accessible; both my roommates said that they had the same problem and that they hadn't done anthing.
The error I get is some random alpha/numerics then "_appcompat.txt" The error doesn't pop up, it's in the "Send Error Report Log." If I try to access IE7, MSN explorer or the web through any other program-it crashes. Now it's not the computer that crashes, just the program.

I ran a search on the net and some people had this problem with Battlefield two, of which I had but uninstalled two weeks ago and for ITunes, which is on the computer, but not being used.

Anyone have any ideas on this one?
Thanks
VistaMulder