I have Painter 4. 5.03, 5.5 and 6.1 working
on 2000 Pro. The only problem I have noticed
is saved JPG's in 6.1 won't open in 4. IMHO if
you can afford it upgrade because there are so many new features to enjoy. I have not had a OS
crash since I upgraded from 98SE to 2000 Pro. It
is very stable.

Richard