Inverted screen display

This sounds suspiciously like a virus or a program running in the background that is causing graphical distortions. Ensure that your antivirus software has been fully updated with the most recent virus and worm definitions, and perform a complete system scan. If this does not resolve the error, you may want to try eliminating programs starting up in the background that could be causing problems. See the following Dell Knowledge Base article for further information:

What is the Microsoft® System Configuration Utility (MSCONFIG)?

I also had this problem, and it was really hard to fix it cos i had to read upside down. It wasn't a virus or start up problem. You have to go to Control Panel,Display,Settings,Advanced,Graphics Card, Rotation!!!!Good luck!