DX8, OpenGL&Quake3

I have a PII400 with a i740 installed, the operation system is win98. I have installed the latest GLSetup, and Quake3 runs well on it. But when I install a Dx8SDK(I have a Dx7sdk installed before), all goes well except the Quake3. The system locks up at the trail screen, I can see the “id” symbol then all is locked up. other games runs well. So I uninstall Q3, reinstall glsetup, reinstall Q3, still locks up. I do not know why. My friend have no problem with Dx8sdk and Q3 on his win2000. Anyone know the solution?