I followed all of the advice posted on this board from a variety of threads (thanks guys) and ran virtually every adware/spyware antivirus, antitrojan program on the market. It would get clean, then respawn. It make a fine mess of windows XP.
It finally came down to cutting one's losses and lowlevel formating, reinstalling, reaquiriing service pack II, etc. The system is fine now and I've put some solid protection on my PC to prevent such a hassel again. All I can say is that ABI Networks/Directrevenu created one nasty bit of malware. My heart goes out to those of you strugling with it.
I'm tracking down a customer feedback email for Microsoft so that I can let them know that due to the vulnerabillites in XP and their (imho) post-hoc solutions, I will be moving to Linux.
The best way to improve windows security in the long run is to demonstrate to MS that it will cost them (and is costing them) market share.
Just wanted to share some final thoughts.