heh, the last time I tried to remove winfixer, I ended up reformatting, however after a search there appears to be a couple utilities to remove this program. You said McAfee is on full throttle, is it a complete internet security, or just anti-virus? If it's just AV, it won't stop things like winfixer from getting on your machine.
Try downloading this and see if it helps for WinFixer:
http://winfixerremovers.org/?gclid=C...A2k64Q#compare
Or try this link here:
http://www.bleepingcomputer.com/forums/topic18610.html
A quick overview shows step by step instructions for removing that garbage. Good luck!