Ur problem can be solved if you perform the following steps:
Right. click on the cs 1.6 exe file
Go to properties
Go to compatibility tab
Check the run opt. in the drop down list select windows Xp service pack 3 (as windows 7 supports the compatibility , it can run also as windows xp)
Right. click on the same exe file (cs 1.6)
Run it as an administrator.
Hope you are enjoying your game.