Hi Mel.
I had some lockup problems with Asus P5A/K6-2/Riva128 combo with both Windows 95 and 98. Especially with Win 95. I sorted them out by downloading new AGP/chipset drivers from ALi's site and updated always to the latest revision of video drivers.
I also remember reading about general AGP related problems on some older Super 7 m/bs related to high current many cards draw from the AGP slot. The solution to this was to modify the m/b to supply more juice to AGP or use an extra power connector on the video card itself. I don't know if Radeons are very power-hungry though.
Good luck with this machine!
Sami