1) Right-click on "Computer" and hit "Properties"
2)Hit "Advanced system settings”
3)Open the settings under performance tab
4)Switch to Data Execution Prevention tab
5)Check the second box named "Turn on DEP for all the programs and services except those i select "
6)Now add the Counter-Striker 1.6 to the list then apply and ok..
7)Now launch Cs1.6 try to change it to open gl mode. Dont forget to reduce the Brightness and Gamma a bit..Then apply.
Hope that works.