This is a common problem with the nVidia 8800GTS Video Cards, the solution is to boot into runlevel 3;
When the GRUB splash screen is displayed press any key.
Select the Linux boot choice and press the 'e' key.
Select the kernel line and press the 'e' key again.
At the end of the line add a space followed by the number 3
When done press the 'Enter' key followed by the 'b' key.
Log on as root and supply the passowrd when prompted
You will need a working Internet connection for the rest.
32-bit: rpm -Uhv http://apt.sw.be/packages/rpmforge-r...l5.rf.i386.rpm
64-bit: rpm -Uhv http://apt.sw.be/packages/rpmforge-r....rf.x86_64.rpm
yum install nvidia-x11-drv
system-config-display --reconfig --set-depth=24 --set-driver=nvidia
Press the three key combo of Ctrl+Alt+Del