Error Drawing Picture after semi-long period of time

I've been encountering a problem recently (started about a week ago, give or take). After about 2-3 hours of the computer being on from a fresh restart, the screen goes gray and it sometimes pops up with an error saying "Error Drawing Picture. Low on System Resources, please close some applications." Please close some applications to continue." If I restart after this happens, it's perfectly fine for another 2-3 hours. I have a GForce FX 5950 Ultra, 2 GB of Ram and my AGP Apeture is set at 256 MB (highest it will go right now). Any ideas?

 

Hi, I can only make some suggestions, haven't had those errors before.

Check for the latest chipset drivers for your motherboard. (I might even uninstall the old ones in Safe Mode first if they are listed in Add/remove Programs).
Remove/uninstall the video drivers in Safe Mode (Add/remove Programs). Install the latest (although some previous versions of nVidia drivers are considered better than some of the newer versions).
Check the drivers using dxdiag (type dxdiag [Enter] at the command line...Run)
You can get a benchmark of your video card at PCpitstop. The drivers may not be working properly if your video rating is much below "standard ".

Even though it looks like a video problem, that "close programs" message may indicate a memory problem. Try the Aperture on 128mb (although you have plenty of RAM to run at 256mb).

Does it happen when you have a certain program running?

Matt