on board video

I have an ibmpc300gl(m/t6275-b9u) that I cannot change the resulution to 800/600. The video chip is s3trio3d on board. I have tried to update the drivers but no luck. I have put a call to s3graphics, no reply. I have tried to disable in bios and have not found a jumper on the board to disable. Ibm is not much help on the website. I have tried another video card but it still goes to the s3. Any suggestions?