I just skimmed messages, but I'm about to go to bed, so I might have missed this: Are you using a PC or a Mac? I'm not sure how to do it with a Mac, but if you want to see what processes are running (look at Processes, not just Applications), hit Control + Alt + Delete ONCE! If you hit it twice, it will reboot your computer. When the list comes up, if you want to turn off any of the programs (be careful doing this; make sure you know what you're shutting off!), select the name and hit "End Process." If you don't want to shut off anything, just click the "X" in the corner to close the window. I don't think this will help you find the problem, but it's possible. Good luck.

This is useful if a program freezes and you want to close it, by the way. If the whole computer is locked up, it may not work (the window may not come up), but if you want to close a program, just select it like I said above, and hit "End Process." For instance, I use Netscape, and if my browser freezes, I just select (under Processes) "netscape.exe" and hit the "End Process" button, and it quits; it might quit right away, or take a few seconds, but after that, I'm usually able to reopen the program and have everything function normally again.