Please try scanning in Safe Mode.
Clean Temporary Internet Files, Cookies and other temporary files:
Check for errors and defragment hard drive:
All the Best!
I think my computer has a virus - it restarts during virus scans (McAfee, panda, trend micro, spybot and adaware) but is basically fine otherwise. I can complete scans by selecting folders on my C drive, and scanning one at a time. I haven't found any viruses this way.