Hi,
It appears that Mechanical Desktop is not completely or correctly uninstalled. Please follow steps as per below post and check if it helps.
http://discussion.autodesk.com/forums/thread.jspa?threadID=713230&tstart=0
Thanks,
Sridhar
Software QA Engineer
Autodesk
Please select the Accept as Solution button if my post solves your issue or answers your question.
Sridhar Subramani
Senior Product Owner