CentOS - Feb 2005 - screensavers stopped working

Hi

First off Centos is Great!!   I have thin clients running under Centos with  
no problems at all !

My question is not a major problem - in my spare time I play a 3D demo 
Unreal Tournment 2003 , just wondering if anyojne knew why my 3D 
screensavers would have suddenly not work?

My video card is Nvidia mX 4000 , no problem running the UT2003 Demo I have 
on it , but for some reason all I get is a black screen where my 
screensavers should be?

cheers

Mike