Just a few weeks ago I encountered a strange virus. It would close Task Manager, regedit, and some other important system functions when I tried to open them. System Restore wouldn't open, either. It also affected other things... like, for instance, if I went to a Web Page that had the word "spyware" or "trojan", or "virus", the browser would close. I tried to run programs such as HijackThis to find out my problem, but HT would close right away. Same with Spybot, Adaware (Wasn't sure if this was a virus or something else), etc. I eventually just downloaded the Norton trial, and it killed it. (No idea how Norton worked)