Tanatos.m or Sality Virus attack: Here is a good solution

Disable system restore service before you start these steps.

1. There is a utility supplied by trendmicro. Its name is SysClean.com. Download SysClean.com from here
2. There are virus pattern files from Trendmicro. Download those Virus Patterns Information here. Note: Download all available virus patterns and download it to one single folder where sysclean is located.
3. Download Spyware Pattern here (somewhere at the middle of the page)
4. Put all files in one folder
5. after downloading reboot your system
6. Boot your system to Safe mode as System administrator
7. Run SysClean.com from where you save it
8. Don’t do anything while the cleaner is in process.
9. After its finished scanning and cleaning open report file to see the viruses.