You can’t start running games, and you have a ATI video card ?

Run “glxgears”, if it crashes, then create this file (ex ati-dri2.conf) inside /etc/X11/xorg.conf.d/

Section "Device"
    Option "DRI3" "False"
    Identifier "Card0"
    Driver "radeon"
# BusID "PCI:2:0:0"
EndSection
Fix running games with some ATI video cards