X Server Configuration?

Yesterday afternoon I installed Fedora Core 4 on my main desktop, and as far as I can tell, everything is working correctly, but I cannot get any GUI sessions started, and I get a message "I cannot start the X server (your graphical interface). It is likely that it is not set up correctly. Would you like to view the X server output to diagnose the problem?" when I reboot; choosing <Yes> leads to a text login prompt; <No> does the same. I have not used Linux in a few years (due to being on a restrictive DoD network), but the Suse 9.0 that was on my computer before and a Knoppix disk both worked fine with my hardware -- relevant parts listed below. ABIT NF7-S v2.0 motherboard, bios 27 3x 512MB Corsair PC3200 ram ATI Radeon 9800XT video card Western Digital WD740GB and WD2500JB hard drives Any ideas would be tremendously appreciated! -- -Nathaniel H. Stickney Amendment II: A well regulated militia, being necessary to the security of a free state, the right of the people to keep and bear arms, shall not be infringed.