Copy ANY Game !!!

[cdkiller]

it´s no good idea.
cause i´m sure the registry entries (like the game path)
are missing, some files are copied into windir and more...

and yes it´s always safe to include the original exe, cause many updates check for the right filesize.

BUT it is possible to compress the installed files and make your own installations. like with Installshield or WISE Installer.