I think what you are describing is the screen just changing from resolution shifts... You probably play the game at a different resolution than what is on your desktop. Also, download Directx 8 (I think that's the most current). I'm sure that directx drivers came with the game but they are usually old. Another option is going to the developer's site and looking for patches for Counterstrike.
Is Counterstrike an addon to Halflife??? If so, then the developer is Valve.