After uninstalling I use Driver Cleaner Pro to clear out any remnants of the old stuff (since uninstalling technically doesn't remove all traces of the old driver..... check your registry, for example...... then again, I'm one of those computer "neat-freaks")......... I don't think it's free anymore, but if you do some searching around you still might be able to find the old version lingering around on some sites.
The last known WHQL driver (Win2K/XP) supported on the GF4 cards is 93.71, but as mentioned above, the 5x.xx series is probably the best to use, seeing as there don't seem to be any real improvements from then on (since NVIDIA concentrates themselves more on fixing/improving stuff in their newer products).