Dr.Web Antivirus – and your PC will be clean!
Virus scan features:

• Dr.Web, a new generation of a virus scanner, searches and kills file and boot viruses, as well as combination viruses, which infect both files and boot sectors.
• The SpIDer intercepts all attempts to access files and disk system areas and checks them for viruses on-the-fly.
• Heuristic analyzer for detecting viruses by signatures.

Trial version for Windows including Vista.