Your graphics chipset should be able to use the vesa driver. You can use the VASM tool as the root user from text mode to fix this. When you use VASM this way, choose XWINDOW -> XCONF. When you are asked how to configure X, don't let VASM do it automatically. Instead, select the VESA driver.
After you have changed your X configuration to use the vesa driver, restart X and see whether it works.