There are many anti spyware programs around these days are some are better than others. SUPERAntiSpyware is a reasonable one to get as it has a FREE version. Anything that's free is better than having nothing at all, even if its not the best.

SUPERAntiSpyware Review

SUPERAntiSpyware is another anti-spyware tool, but the free version requires you to manually check your system. It will look for and detect the latest worms, Trojans and other problematic applications, but it won’t block these on a ‘real-time’ basis, nor can it schedule to check on an automated basis. You’ll need to perform these tasks manually. This is the ‘free’ version. The Professional edition will schedule, automatically check for Trojans and will update definitions automatically.

This is the official release of the major new revision. New features include 30-50% speed increase over the previous version, enhanced in-memory detection, improved protection for Vista users and much more.