The thread discusses the possibility of using a Windows 7 installed on a laptop's hard drive on a different desktop running XP. The second poster clarifies that OEM versions of Windows are not transferable, only retail copies are. The third contributor emphasizes that Windows licenses are rights to use the software, not ownership, and suggests purchasing a full version of Windows for full rights, noting that Windows 7 sales have been largely discontinued but legal copies are still available. Overall, the consensus is that transferring OEM Windows licenses is not permitted, and buying a retail copy is the best way to ensure legal and flexible use.