That MAY be a graphics adapter problem
What is your exact brand/model graphics adapter (ATI or nVidia or ???)
What is your exact graphics adapter driver version?
Have you gone to the vendor web site to check for a newer driver?
For Windows, do NOT rely on Windows Update to have current driver information
-you need to go direct to the vendor web site and check updates for yourself
ATI Driver Autodetect http://support.amd.com/en-us/download/auto-detect-tool
nVidia Driver Downloads http://www.nvidia.com/Download/index.aspx?lang=en-us
What version of Premiere Elements are you working with and on what Windows 7 is it running (32 or 64 bit)?
Are you saying that this problem exists when you go to open a new project (no media introduced into the project yet)? Or, are you trying to open a project that has already been created/saved/closed?
Is this a "it worked before but not now" or "it never worked before" problem? If it worked before, how long ago was that and what were you doing when things went from good to bad?
Information that John asks about your video card is important and should be ruled in or out at the onset.
Let us start here and then let us decide how best to customize the troubleshooting for your specific issues.
thank you very much for your hints - I spent all night yesterday to update the ATI drivers and check the SW reaction. It seems, that the issue is solved.
Thank you very much for helping me out, it's been a terrible situation.
Good job you and John in getting to the core of your issue so quickly.
Was the fix just updating the ATI driver or in adjusting some of the card/driver settings as well.
just installing the latest driver seems to fix the problem. I keep you posted, if I see similar issues.