counter strike help!

[phycokillaman]

when ever i play counter strike for about 15-25minutes it always freezes goes to a black screen and says optimize 1440 x 900 and the computer locks up i cant get out of that optimize screen o and btw my email is phycokillaman@hotmail.com

 

[Darth_Terra1]

Please post your System specs it's hard to diagnose a problem with out knowing what you have.