I think I have the answer. Had the same problem myself and found the answer on: http://www.ntcompatible.com/n.htm
The way message 5) system #4 solved his problem worked for me to.
Your problem is probably not the new graphics card - but the increased RAM
You should decrease the initial paging file size in Windows.
My system with 256 Mb RAM only worked after decreasing the file size to 256-500 Mb.
Try it.
P.S. I also tried deleting "gimme.dll" - did'nt work.