Spybot Search & Destroy works great for MOST spyware.
Hijackthis works great if you're having a browser hijack problem.
But the best way to prevent spyware and such is to just do a few simple things.
#1) Keep a firewall on and configured. I suggest zonealarm, but for some people I could see it being a bit confusing.
#2) Keep windows up to date.
#3) Turn off install on demand on demand
Internet Explorer > Tools > Internet Options > Advanced Tab
Uncheck "Enable Install on demand," both variations.
and that's all I do. I haven't run a virusscan on my computer since June. No problems at all.
