Crashing on log out.

I had a lovely install experience with RH 8.0, best so far. However, On 
trying to logout of the system the machine dies.

I get a black screen and the caps lock & scroll lock lights flash. 
Nothing works apart from the power off button, thus I have no ability to 
further diagnose the problem. This happens everytime.

My machine is:

Celeron 433
i810 based mobo
192MB memory

Any ideas?