[plug] Tracking down X server problem - Hardware?

[Tim White]

I have a box that randomlly freezes the X server. It used to run windows 
with the exactly same hardware and never had the problems. When it 
freezes the Keyboard and mouse stop responding and the display stops 
updating. I can ssh in and kill the X server and all works fine again. 
This happens with a local X server and a remote XDMCP session (with the 
computer as the client, not server)
It has a ps2 mouse and keyboard. TNT2 graphics card. It is running 
Xfree86=4.1.0-16, Debian Stable, with a 2.6.6 kernel and the Nvidia 
modules compiled agains the kernel.
Nothing appears in the logs and just killing some of the xclients fails. 
I have to kill the X server.
Any clues as to how I can track it down?
Thanks
Tim