I've used McAfee AntiSpyware, latest versions of AdAware and Spybot, and I still can't get rid of Winad.exe. Even if I clean out everything (normal and safe mode) things reappear when I reboot. Here's my Hijack This log.
Logfile of HijackThis v1.98.2
Scan saved at 7:37:13 AM, on 9/26/2004...