I wonder why CWShredder worked for me. Other variations of Cool Web Search much more devastating?
You were fortunate. There are apparently all kinds of variations. This site taught me a lot:
http://forums.spywareinfo.com/index.php?b=1
CWShredder is a magnificient program but, much like real life viruses, the spyware 'diseases' are constantly evolving. This is not something that you can run and expect that your machine will be clear forever. On all the adware/spyware removal tools, you have to download new additions constantly and also take steps to secure your system as well.
[I once spent 3 days getting CoolWebSearch off of my wife's machine because NONE of the tools at the time would do the trick. I won in the end, though!]