My Monitor Screen Keeps Moving Up & Down - What Would Cause That?

[highbids]

I've been having issues with my monitor screen moving up & down at a high rate & I'm thinking it's a bad driver or would a virus do it.

Is there a software program that can diagnose the problem
here's my computer & video specs.

Computer: Dell DImension 8300 2.8 Mhz
NVIDIA: GeForce4 MX 440 with AGP8X
Monitor: COMPAQ 7500
DivX Plus Directshow Filters
DivX Plus Web Player
Java 6

 

[Tmagic650]

Swap monitors, or try the "jumping" monitor on another computer