Black screen in SolidWorks

I have som problems with a recurring black screen.

I can't say exactly when it appears, but almost all the time when I'm building models and clicking between different windows in SolidWorks.

It disappears when I rotate the object.

I've experienced this problem on this computer for a week, after having SolidWorks installed for another week without any problems.

Another thing is that I can't now have more than one part open at the same time. If I open a new part, the window will only show a frozen image of the first part.

I have tried to reinstall both SolidWorks and Windows 7, none of them works.

The Computer is new and barely used for a couple of weeks.

Specs:

Dell Latitude E6420

Windows 7 64-bit

Intel Core i5, 2,6 GHz

SolidWorks Premium SP4.0 2011, 64

My Graphics Card scores 4.7 on Windows Experience Index

Have anyone else got the same problem and know a work-around or solution to this problem?

/Marcus

SolidworksUser Interface