have you tested the file(s) at www.virustotal.com

running multiple AV programs can create all kind of mysterious windows errors and false positive detections

Never install two AV programs (see reply from quietman7)
http://www.bleepingcomputer.com/forums/index.php?s=7c8217673a726b92cfc91ecfd4294a29&showtopic=260844&view=findpost&p=1441638