I have a Dell E510 desktop with a geForce 7200 instead of the ATI x600 it came with.

I have attempted to install CentOS 5.4 x86_64 (DVD), CentOS 5.5 (net install), and CentOS 5.5 x86_64 (DVD). Gnome desktop. All of these run into the same issue.

When I put the DVD into the machine and reboot, the installer begins and I select "graphical install". I see text that say anaconda is starting, and then my screen goes nuts. It's not black, but rather a screen full of diagonal stripes or multiple colors.

So I attempted to do a text install of CentOS 5.5 (DVD) and got it installed. When I booted for the first time, I logged into the virtual console and started X (startx). The desktop came up and it already had the display properties GUI up. I changed it from 800x600 to 1680x1050, saw that there were updates available, installed them, and then rebooted. When I start X from the virtual console this time, I get exactly the same display problem as I described before.

Does anyone know what might be causing this and what I can do about it?

edit: I should also mention that I'm capable of installing Windows 7 and Ubuntu 10.04 onto this machine with absolutely no issues at all.