If you are using XP, you also need to get it out of System Restore. many viruses use this to re-populate. Make sure you have a good backup of all your important files and your Registry. Then go to the System Restore in tools and turn it off. This erases all of the backups. Then run your antivirus again. Then turn system restore back on after the machine is cleaned.
It's been said already but yeah. Try system restore FIRST if you don't want to lose all your data and then try a complete format if the anti-virus software doesn't work. Sometimes the virus is just too powerful for it to handle when it gets in.
Well, yesterday Malwarebytes picked up Trojan.TDSS and quarintined it. I ran another virus scan and that was clear, so I turned off system restore, and rebooted and started the scans over today. So far so good. Nothing was picked up by Zone Alarm, or Malwarebytes. I'm going to run both again tommorow, then turn back on system restore, and then reboot and run a scan of each again. If all goes well I fire up Acronis and get the backups on automated. If you know a hacker who writes this crap, do us all a favor and kill him or her, or at least post their name and address for the whole world to see. Thanks