According to ATI support, their Rage Mobility is computer specific and that is why they don't supply drivers. Well, my computer producer Fujitsu doesn't support NT4.0 either. I was desperate.
This driver was the solution. It is DELL Inspiron 7000 display driver, but works great with my Fujitsu LifeBook C-6525 (actually, F. Biblo NE2/450L, but the same thing).