I have Windows 64-bit ultimate for sale. It has a keycode and It has been used but is not any longer. $35 shipped for anyone interested.
If as you say it "Has been used" -- the key is worthless and not resaleable as the OEM versions are tied to the initial MOBO they are installed onto thus unless you are selling the MOBO along with the OS it is illegal to resell it and anyone purchasing it is getting a useless key since the authentication server has already paired it to the original MOBO and the license dies with that MOBO and is non transferable !