Quite strangely enough this 'change' makes no difference what so ever, however I have resolved the problem now by testing WPI on a system NOT using Virtual PC and both my switches and yours work without problems. My Virtual PC installation renames some of the drive letters which includes the optical drive and perhaps this is what creates the issue with WPI, im really not certain. But outside of Virtual PC all works correctly Just thought I would mention it incase anyone has similar problems