........I get a virtual memory low warning and the whole thi......
This sounds like you may also be short on RAM. This also affects your FS performance. I think the general concensus is min of 512Mb for an XP system. I saw significant FPS improvement/elimination of stutter upgrading from 256 to 768. New 512Mb PC2100 DDR ram, $75-80 US.
If your stuck with only PCI (as I am) for your Graphics Adapter upgrade, I believe the Geforce fx5200 128 PCI is about the highest you can go (dont know about ATI). New, $75-80 US. For AGP, think new is about $55 US.
Cheers,
Dave
At that time [1909] the chief engineer was almost always the chief test pilot as well. That had the fortunate result of eliminating poor engineering early in aviation.