try System/Preferences/Appearance/Visual Effects : select 'none'
Also, turn off your screensaver while you play.
Also, there is an old Ubuntu issue that this COULD be, and it was b/c there was a USB plugged in @ boot. For some systems running Lucid this is still a problem. Unplug any USB (flash/media drives, not mice or cooling pads, etc) b4 starting up.
If this doesn't work, and you have an Nvidia graphics card, as a last resort you could try the ppa drivers and reconfigure X.
Honestly it's kind of hard to tell you what's wrong with such little info, but generally this kind of thing is related to your graphics in some way, meaning Xorg, Graphics Cards, Monitors, and as Nativo mentioned, Desktop effects. COMPIZ SUCKS!
Also, turn off your screensaver while you play.
Also, there is an old Ubuntu issue that this COULD be, and it was b/c there was a USB plugged in @ boot. For some systems running Lucid this is still a problem. Unplug any USB (flash/media drives, not mice or cooling pads, etc) b4 starting up.
If this doesn't work, and you have an Nvidia graphics card, as a last resort you could try the ppa drivers and reconfigure X.
Honestly it's kind of hard to tell you what's wrong with such little info, but generally this kind of thing is related to your graphics in some way, meaning Xorg, Graphics Cards, Monitors, and as Nativo mentioned, Desktop effects. COMPIZ SUCKS!