Question : Problem: Challenging PC Diagnosis

I'd like to zero in on the likely causes of something I've never seen before nor can quite imagine how it's happening.  So, I'm looking for suggestions:

Windows XP
Monitor goes black suggesting that the video signal has gone.
The monitor auto adjust message comes up - then the video returns.  Also suggesting that the video went away.
This only happens when one is typing lots of characters - that's how I was able to trigger it .. actually quite often.
Otherwise, I didn't see it happen at all.

The normal user reports that the computer "freezes up" at these times but I haven't seen that phenomenon.
When one isn't typing much, the monitor seems to work fine.
The typing test does this:
Open Word, blank document, randomly type characters as fast as you can with no sense to them just bang away at the keys for max character speed.

The system has been scanned for parasites with a separate program and has a good internet security suite running all the time.  No parasites found or suspected either....

Answer : Problem: Challenging PC Diagnosis

System specs? Try another video card. How do the voltages look in the bios pc health page?

Chris B