I'm not sure if this is of any help, but I was running PCLOS 2007 on a desktop machine with onboard S3 graphics of about the same generation you seem to be running. I kept beating my head against a wall trying to get 3D acceleration to work, and finally got it fixed by removing all video drivers except for the S3 one I needed. Once I dumped all the Nvidia and ATI drivers the S3 driver took and worked, and my graphics worked fine after that. Not sure if this might help, but figured I would mention it just in case.