Game Instalation Problem

On my laptop, i cant play none of the games i downloaded on here. I always get a message saying somethin about i’m missing a dll file every time i try to run or install a game. I tried wit Command and Conquer generals,Resident Evil 4,Painkiller,and Hellforces and every time it says im missing a different dll file. :
Answer #1
if the missing dll starts with dx
then u need the directx update
http://www.microsoft.com/downloads/details.aspx?familyid=1A2393C0-1B2F-428E-BD79-02DF977D17B8&displaylang=en