There isnt really much point backing u pthe entire game folder as that contains lots of files that are extracted during installation and if you took those files and put them onto another PC, that u had not used the installer to install the game, the game would just not run.

You would need the installer file .
Your best to just save the game files for ur profile, this is a lot smaller, and then just re instal the game using either the CD or download the installer again.

and then ur saved game files can be copied over so u dont loose ur progress in the game