Erm... what is the problem? You can't log in with a new account? Make yourself clear, man! Only explorer? Anything else? If it's only explorer, I recommend you get a working explorer or reinstall windows. Maybe a trojan is not working well. Get explorer from someone else and copy it over. If you can use the computer somehow, you can zip and post the explorer.exe here so I can see if it's ok. If other things are erroring well, there might be more things at play. In that case, do this: Run Prime95 for an hour and memtest86 for 4-5 hours. See if they find any errors (they test the CPU and memory). I can't say much about anti-virus, since I never use them and I remove all trojans manually, without any AV... Erm... well, let's try the manual route a bit: Try Winternals Autoruns and disable any suspicious startup programs. If you're not sure what the bad stuff is, save the log from autoruns and post it here so I can tell you what to try disabling. Also try RootkitRevealer. Maybe your computer is infected with a crappily made erroring rootkit. If Continuum runs (at all) then it is not an old-fashined virus. Well, I haven't seen those in many many years, so heh. Yeah, those are quite dead. All in all, clarify the issue.