Try a couple of these free, online scanners to see if anything has slipped by your protection (most require that you use Internet Explorer):
(Be advised that some of these scanners will pickup things in "quarantine" from other anti-virus programs - so review the results carefully)

http://us.mcafee.com/root/mfs/default.asp
http://housecall.trendmicro.com
http://www.bitdefender.com/scan8/ie.html
http://support.f-secure.com/enu/home/ols.shtml
http://onlinescan.avast.com/
http://ca.com/us/securityadvisor/virusinfo/scan.aspx
http://www.eset.com/onlinescan/
http://www.ewido.net/en/onlinescan/ - thanks to Tehsplink!  added 17 Feb 09
http://www.windowsecurity.com/trojanscan/ - thanks to Tehsplink!  added 17 Feb 09
http://safety.live.com/ - follow the prompts to use the scanner for Vista/Win7

http://www.kaspersky.com/virusscanner  Scan Only - no removal

http://www.pandasecurity.com/homeusers/solutions/activescan/  Scan Only - no removal

If you find that you're infected (or the scan doesn't complete or closes unexpectedly), post in the Am I Infected forum located here: URL removed
If you're not infected, post back in the original location and we'll try some more stuff.