Spywareinfo.com has a lot of good resources, including CWSHREDDER.ZIP and HIJACKTHIS tools.
I've found that spybot and adaware are about 90-95% similar, but, you need to run both to catch everything. Then run CWSHREDDER.ZIP. Then you have to run msconfig and check the run tasks to make sure there aren't any weird name tasks re-installing stuff on bootup.
NOTE: SpyBot's updates do not take effect until you restart it. Some of the updates restart it automatically, but, if not, after doing theupdate, close it and restart. Then scan.
After all that, Hijackthis is usually not needed, but it's a good tool to have.
You may then want to download and install spywareblaster, from
www.wildersecurity.com (you can get to it from spybot's immunize tab also). There are a bunch of updates that block bad scripts.
MyIE2 is a good, free IE Frontend, seems to have picked up where crazybrowser has left off. Still I use crazybrowser most of the time and it seems to catch all the major pop-ups, but, I'm transitioning to MYIE2 which appears to be >= Crazybrowser. I haven't played with the other browsers much, so, can't compare there.
