Screen turns black while playing

eeeeeyyyoooo

Hello

This is what happends:
Sometimes when I play.
Sudenly the game just freezes.
After a while I hear lots of noice (The nades and stuff explode then all at one time)
And my screen turns black.
Then I push ctrl alt delete and click the crossfire thing again.
After about 1 minute i can play again.
This is realy REALY annoying.
Annyone who can help me

Thanks for reading