xserver

hello! when i run many programs my xserver restars!!!! ->logout and i have to login again! Some times my xserver restarts even if i don't run any program !!!does anybody have any idea about my problem? i run memtest and i didn't have any problem.... does anybody have any idea????? -- Na xaireste to Linux kai ti Zwi! University of Thessaly Computer and Communications Engineering Dept. (C.C.E.)