Ah, you didn't mention there were viruses.
I would post a HijackThis log for a log specialist to take a look. HijackThis is available here:
http://www.trendsecure.com/portal/en...kthis/download
Use "Do a system scan and save a log file", and notepad will open with a log of what it finds, copy and paste the contents here. Don't ask it to fix anything.