I have Win XP and an Nvidia card, but have had no problems with other programs other than Poser5...what are the known programs that don't work with XP and Nvidia ???? ....and quite frankly, I think the problems I see have no relation even a little bit, to the graphics card..at least on my system. However, quite a few Poser 4 light sets cause instant freeze when that render button is pressed...not sure why, but its pretty consistant. As far as drivers, it is possible to install new drivers without uninstalling the old ones...which can cause some mighty strange problems...so, if you are going to reinstall drivers, make real sure you have deleted all evidence of the old drivers prior to reinstalling. Another driver issue...everyone offering advice on drivers makes the statement "make sure you have the LATEST drivers"...but is that actually the best policy? Especially when a program was written prior to the last 3 or 4 versions of drivers even being released??? Did you ever think it may be more beneficial to go to the Nvidia driver archive and try an OLDER driver package??? You may be surprised at the result.

Humankind has not woven the web of life. We are but one thread within it.
Whatever we do to the web, we do to ourselves. All things are bound together.
All things connect......Chief Seattle, 1854