One of my monitors has a loose connection where the video cable plugs into it.
In my case, I need to ensure that the plug is properly pushed home and the two little screws are done up nice and tight. It's either the connector inside the monitor or the lead that's a bit dicky.
It's worth checking before you think about changing graphics cards..
A new monitor 'might' do it too, but it's more likely the graphics card. I would certainly check. You might be able to plug the monitor into a laptop to check it.
For those using AVG free. Version 8.5 will no longer be supported from 1st Dec '09. Replacement is version 9. This now has lots of functions running in the background & is definitely slowing my laptop down (CPU usage monitor shows surges up to 20% resource being used with nothing else running) so advise running 8.5 for as long as you can. It is also making Java hang when exiting a screen. Might switch to Avast but already pay for registry cleaner & anti-spyware. AVG has always been next best, imo, but not any more.
I don't doubt others who are more PC savvy than me - but I can't say I've ever noticed any slowing down myself - and I've run AVG for years because I like the way it just gets on with things without causing me problems - unlike my previous use of Norton which I found very troublesome as well as a continuing expense.
I think Norton's bad rap is largely no longer justified.
The current Norton AntiVirus (2009) just doesn't seem to have those old problems. The control panel even has two bae meters showing 'System' and 'Norton' CPU usage - they obviously felt they had to demonstrate the improvement.
Also, you get three licences for your sub.
For me, it has one fault (and always has had). I have to turn email scanning off, as it stops all my POP3 email transfers via Eudora from completing. In practice, this makes no difference, as a virally loaded attachment always gets spotted as its stored. Still a weird problem, though.
If removing three cards caused solved the problem, then it could be a failing power supply or motherboard. As the failing component gets worse, the problem may come back.