256 color resolution is missing

Problem: I did a clean install Win98 SE on a computer donated to our school and the color resolution does not include 256 colors. I went to properties settings advanced and selected the adapter tab and the card is listed as a Standard PCI Graphics Adapter (VGA). Manufacturer: (Standard display types) Software Version: 4.0 Current files: vga.drv,*vdd
Since this seemed vague I opened the box and found out I have a Matrox Graphics card. I think the right number is G2+/MILA/8D/CPO. I went to their site to see if there was a download and couldn't figure out if one was there - I tried several and could not find an exact match. Prior to opening the box I tried the suggestions on the 6 pages of archives on this site and nothing worked. A quick run down includes: unistall through device manager, putting the short cut icon on status bar, searching the 98 install disk for a driver for display, and 6 hours later I still have not solved this problem. I have 5 other computers with this same problem. Please help.
Thanks