Most OS disc came with computers are just for recovery on that
machine. However, some companies still offers an option where you
can pay a small fee for a full OS package disc.
However, unless u purchase a mass lisense, i think even if you can,
you are only legally right to install 1 copy to 1 computer. Using 1
copy of windows on more than 1 computer at the same time might
place ur OS in Microsoft's blacklist, thus marking it as illegal
and deprived u all your rights to enjoy security upgrades.