How to install certain part of the game ??

I think what you mean is registry entries and things like DirectX, C+ Redist, PhysX and things like that. And no there is not a way to install those only, you will need the original installer for every game you are trying to copy. If they were from steam then just stick the main data back into steamapps folder and delete executables, re download from steam and let it do its thing. As for anything else installed from a CD or whatever, you will need original installer

Thanks for the replies
but I have many games installed
and re-installing them will take a lot of time
and I have all the DVDs

Best answer selected by bayern.

OK
Thanks