Uberpare, if you bought W7 retail in a video tape type plastic pack from a store the licence(certificate) of authority (C.O.A.) is yours for life. You can use it on any one pc at a time, change as often as you want, and use 32 or 64 bit, with that code. It seems W8 even o.e.m. will do the same.
Sell ur Microsoft shares! Thanks for the vote.