Did you try to use a online scanner? like http://housecall.trendmicro.com/ ?.. some of the trojans/worms out there disable your virus scanner on the computer, then it infect the scanner and make the scanner miss it, this wont happen if you use a scanner from the net.. try it and maybe it help you..

if ($me != tired) { return } | else { echo -a Get a pot of coffee now $+($me,.) }