[cavedude]

You may have an infection. More than likely spyware, and the thing you need to know about spyware is one program is NEVER enough. Spybot, like all other anti-spyware programs on its on SUCKS. But, if you use spybot, ad-aware, ewido, M$ defender, etc all together than you have quite the defense. Also, you'll need to make use of tools such as hijackthis, autoruns, and Winsock XP Fix to fully get rid of most infections. The other thing you need to know is there isn't a single anti-virus program on the market that effectively fights spyware. Sure, they can detect a couple of variants here and there but they can't completely remove them.

So, I recommend grabbing as many anti-spyware tools as you can (starting with the ones I mentioned above) install them, boot into safe mode, and do full scans with all of them (let your machine scan over night) When they are finished cleaning, run hijackthis and autoruns, remove any suspicious entries either finds. Hell, if you don't mind reinstalling a couple of programs, remove everything both find EXCEPT Microsoft entries and your device drivers (though keep an eye out for any odd ones). Run Winsock XP Fix to repair your winsock, and reboot into safe mode again. Run hijack and autoruns again. If any of the entries are back (and they aren't obvious ones that aren't malicious) track down the file, remove it if you can, remove the entry and reboot again.

In most cases that should clean your machine. Many exceptions apply, but the scanners will tell you everything you need to know. If something lingers, do a search on the web for manual removal directions.

If it still doesn't work, then I would recommend backing up any user data, formatting and starting fresh. A backup image is useless if it too, is infected or has the problem.