Anti SpyWare programs are great but not fool proof. From a recent article....
"While cleaning out a friend's computer, he discovered a spyware file holding 3GB of information.
"Anti-spyware in the machine can appear to work properly, and then in the background there's this file, three gigs of information stored away, just sitting there," Gilroy said."
Quoted from
http://news.yahoo.com/news?tmpl=story&u=/pcworld/20040419/tc_pcworld/115735