That this machine has Vista. I see no model number so you are not asking others to find a driver.
Given this much all I can offer is that Vista has a compatibility mode for 256 colors. Read http://www.instructables.com/answers/How-do-I-make-vista-run-in-256-color-mode-for-a-ga/
I love the original Hover game that came with the Windows 95 operating system. I have this game, but don't have the 256 driver so the game looks weird. Can I install a 256 driver on my Gateway that has Vista operating system? If so where can I go to get the correct driver? Thanks, smorgan3881