This may be a problem linked to compatibility between your VIA chipset and the Graphics card. I had a similar issue which i resolved by setting the AGP aperture size to 64mb in the BIOS. The AGP aperture defines how much system memory the graphics card can potentially use, on most games sizes like 128 and above aren't necessary (the game never uses it) as it's mainly used for storing texture etc. Try changing this setting and see how you go.

This info may help also, i think that could be your problem. For VIA Info go here.

Hope you get this resolved & welcome to the Org btw.

*Ringo*