n01getsout

Malwarebytes' Anti-Malware is a free on-demand anti-spyware application that is capable of detecting and removing some of the worst malware that other programs miss, including MS Antivirus (also known as XP AntiSpyware 2009). It also bundles a utility called FileASSASSIN that can delete locked files from your computer.

The non-free pro version allows real-time monitoring that can stop spyware as it trys to install itself on your computer. It also allows you to schedule automatic updates and scans. The license is a one-time $25 fee, which according to the Malwarebytes forums is a lifetime license that will be valid for all future versions.