So, i re-installed W7 and 11.6 ATI drivers given by my graphics card's manufacturer.
It little resolved the problem but in Counter Strike Source, I can play but sometimes the game freezes and displays a black screen. After , it replays.
In Windows Events :
A problem with the video hardware caused Windows to malfunction.
Name of event : LiveKernelEvent
System version: 6.1.7600.2.0.0.256.1
Language : 1036 (French)
OS Version: 6_1_7600
Service Pack: 0_0
Recipient ID : 0x117_Tdr:2_IMAGE_atikmpag.sys
Server information : 5ceea6de-3a4d-485f-98d0-cb39ffe302fc