Have you tried re-configuring your X server? If all you're getting is the text login, then login as root and type xconfigurator
. I can't remember if it begins with a small x or a capital X - best just press x and then press the tab key a couple of times to find out.
XConfigurator will ask you some questions about your hardware, but none should be too taxing if you've got all the manuals and whatever.