Do you mean the annoying monitor blanking after 10 minutes inactivity, or an actual screensaver software like xscreensaver? If it is just the blanking, you could turn it off in X server configuration:
Code:
Section "ServerFlags"
Option "BlankTime" "0"
Option "StandbyTime" "0"
Option "SuspendTime" "0"
Option "OffTime" "0"
EndSection
I don't known where the X server configuration is exactly in your CentOS version, it should be a file "xorg.conf" or optionally (in newer X versions) a directory "xorg.conf.d" with several files. In both cases under /etc/ or /etc/X11.