Unable to Use ATI Video Card Driver for 3D Graphics

I'm running Mepis 6.0 on an AMD Athlon 1.3 Ghz processor, 384 mb memory, old 17 inch monitor. I recently installed an ATI 9200SE video board so that I could have 3d graphics. When I click on the add ATI official driver in the Mepis OS center and reboot the regular 2D graphics cause lockups. The system freezes and the only way out is the reset button. When I edit the xorg.conf file to set the driver from fglrx to ati it works fine but not for 3D graphics.

I've tried dozens of different options in the xorg.conf file with no success. A tech from ATI thought it could be an old BIOS causing the problem so I upgraded it to the latest one for the motherboard dated 20030810. Another guy thought it might be an inadequate power supply so I upgraded it to a 550 watt supply. I've tried both the fglrx driver install using the MEPIS utility and installing the driver using the install program from ATI.

The MESA driver works OK for 3D graphics but it's kind of slow. The graphics card works great using W98, but W98 kind of sucks compared to MEPIS.

Any ideas on what might be causing this? Thanks.