3D just went away!

Have an ATI Rage Pro 128 4X AGP. And my ability to play TuxRacer just went away one day. SimplyMEPIS 2004.03, updated regularily with Synaptic. Recognize the symptoms as not having 3D enabled. In one user the screen stutters slowly. For my other user the screen goes black and I get a nice big white cursor. (Why different a mystery.) It did work before. The only change I can remember is going through Mepis System Centre to change the monitor settings to my actual NEC monitor. Not a big deal. I can change to my Mandrake system to play when my grandson comes to visit. But it is very odd. Thanks in advance.