Either invest in a system backup and Disk Format utility or switch to Linux.

Microsoft doesn't want users to rely on Anti-Virus Tools since detection of viruses is getting difficult, and remediation is often impossible. Therefore, Microsoft urges to format hard discs and reinstall everything from scratch if their computers are infected with sophisticated malware.

Even though anti-virus technology is improving, Microsoft accepts that traditional approaches [ Microsoft Malicious Software Removal Tool included ?] are failing in the face of more sophisticated malware and highly-motivated profit-driven virus writers.

Microsoft finds the cleanup process in such cases "just way too hard."

Microsoft Research: The Strider GhostBuster Rootkit Detection

Sources: The Register | eWeek