Windows 2000 Desktop is Upside Down

I have seen some strange things, but I encountered something that takes the cake. One of the users that I support has a portable computer that he uses in the field. He reported to me that when he boots it up that when he logs into Windows and all items on the desktop are upside down. I logged onto his system and sure enough everything on the desktop was upside down. I checked for viruses, but no reported problems. I even tried a repair with the Windows 2000 CD, but to no avail. Anyone come across this one and any suggestions?

Mike