Screen Bounces

I have tried unsuccessfully to find the solution to this problem. Periodically in Windows Vista the screen will bounce like crazy. It doesn't matter what program I'm in as long as the cursor is on the main window. The screen will stop bouncing if I move the cursor to the top or bottom status bar. I have check all the drivers and video card connections as well as the monitor cable connections. Firefox list a "fix" by manipulating the bookmarks. This occurs whether you have the Internet open or not. All virus and malware scans come up clean. Can anyone help?

Re: screen bouncing

Is there a fan near the computer monitor ?

Yes, a small desk fan will affect your monitor screen, well, CRT screens. I am not sure about flat panels.