Windows 7 on a new desktop- OEM or not OEM?

[Banterlopes]

I am buying a new desktop and I'm looking to put Windows 7 (64 bit) onto my desktop. Can anyone give a dumbed down edition of the OEM story and is it the right way to go? Are there other editions of Windows 7 that you can use, maybe buying an old XP and getting an update copy?

I apologise if I fail to make any sense, I basically want to know what to do to install windows 7 on a new desktop.

 

[DiaSin]

OEM is locked to the system you install it on, more specifically the motherboard. As long as you do not change the motherboard you can re-install an OEM copy on the same system as many times as you want from my understanding. If the mobo dies you have to replace it with the same model, or buy another copy of windows. Basically it comes down to how much upgrading you plan for the future. If you plan on changing motherboards get a full retail copy.