S3 is a driver. I have used it before. It is available in Mandriva's /usr/X11R6/lib/modules/drivers.
Thus I would follow Pixellany's suggestion and edit the /etc/X11/xorg.conf and in the
Section device
change the driver statement to this
If the Linux mismatches the video card driver the standard error is no screen found. One or two of the drivers in the above subdirectory will kick start the PC. At leas that is how I survive so far without the need to install a video driver myself. Not one driver out-sourced in all the Linux I installed and I believe everyone can do it too.
Actually in Mandriva, as in many Linux too, one can run the program "xorgconfig" in a root terminal to configure the Xwindows any number of times. The video section has about 100 cards to choose from. Just checked myself "s3" is one available for selection too.