Can someone help me with a problem HALFLIFE/COUNTERSTRIKE
 

My neighboor let me have his Halflife/Counterstrike cd and he gave me the cd key etc When I install it and enter cd key etc Halflife works fine but now that I downloaded CS the cd wont work for either game it tells me it is invalid and the cd is the original one it was not DLed or pirated etc.

sounds for me like a patch problem.
you need latest counter-strike (1.5) with latest half-life patch (1.1.1.0).

only installing counter-strike is not enough.

Already have all the newest patches I think I might jsut buy the retail

when using the retail version make sure to visit www.nextwish.org as there are some vital files missing in the retail version !

install half life

install latest half life patch

install latest cs patch