KDE Won't Start, Gnome, XFCE will

[Eric]

Hi,

I have Ubuntu 8.10 installed and I assume XFCE was installed when I 
installed Ubuntu. They both start and run fine on my PC. I also 
installed KDE. KDE will not start. I have booted into a terminal even 
and tried to get it to start from there. I get an error that says 
"Nvidia OpenGL driver requires CPUs with SSE to run." This seems strange 
to me since Gnome and XFCE will run.

Mandriva One which uses KDE 4.1 will also run on this same computer.

Any idea what the problem might be or why the Nvidia drivers are ok for 
everything I've tried except KDE on Ubuntu? I would prefer to run KDE.

Eric