When running games in OpenGl, like Counterstrike and Quake3, you might have problems with a laggy mouse (+ keyboard). This lag CAN be related to DirectSound a part of DirectX; the solution was found by "Cabrone":

1. Go to DirectXDiagnostics; Start -> Run -> dxdiag.exe
2. Just go to the sound part of directx and disable sound acceleration

This tweak clears up the laggy mouse issues in OpenGl games under XP