A useful tool to block Spyware websites:
Innoculate
Inoculate is a portable software program for the Windows operating system that will add more than 14000 spyware websites to the Windows host file. These 14000 spyware websites are blocked from being accessed by users of the computer system. The software creates a backup of the current host file before it begins to add the spyware websites to it so that spyware attacks and spyware programs are automatically blocked.
[Source: gHacks]