If you are ever infected with spyware, this will do its best to clean your system.  Personally, I have still had problems clearing everything.  For some reason, some of the adware that found its way onto my computer was missed by this program.  However, it does remove quite a few unwelcome bits of code, so it is better than nothing at all.

Link: http://lavasoft.element5.com/software/adaware/

This is an excellent (and free!) firewall package that has probably saved me from countless viruses.  I only wish had installed it before the Blaster and/or Welchia32 worms did a number on my hard drive a while back.

It is easy to use, but I should note that it does have to go through a brief learning period during which time you have to tell it which programs to allow access to the internet (e.g., your web browser(s), email programs, etc.).  This is annoying, but it is an essential step that at least gives you control.  You can always revise these permissions later if you need to.

Link: http://www.uant.net/firewall/zonealarmguide.html