What parts need selling with windows?

Technically, the motherboard, but I think any 3 items changed will trigger a Windows authorization error. Just sell the PC as a whole, easier to do than selling the parts. If you are replacing everything that is.

Im using the case, psu, GPU and HDD in my new build so can't sell it as a full pc

I've purchased Vista COAs on bits of base plastics and activated it on completely different machines, but often as not had to go through the telephone activation rigmarole which is a lengthy pain, but works... Guess if you offer the licence for sale strictly speaking you'll have to offer a part of the old machine to comply, make it a small bit to save postage!

From a licensing perspective,as far as windows 7 is concerned, Microsoft considers the motherboard to be the essential part of the computer. You can upgrade/change any other part you want, but if the M/B goes so does your DSP/OEM version of windows. COAs are legally sold only by manufacturers along with a PC, with the OEM/DSP disc together. Sites and companies selling "orphan" COAs are actually selling pirated software.

So selling it with the motherboard would cover you license-wise. The only case where change of M/B is permitted without repurchasing Windows, is if the M/B dies within warranty and is replaced by the manufacturer either with the exact same model, or a different manufacturer-designated replacement.

From Microsoft Answers:

OEM versions of Windows 7 are identical to Full License Retail versions except for the following:

- OEM licenses are tied to the very first computer you install and activate it on

- OEM versions allow all hardware upgrades except for an upgrade to a different model motherboard

thank you. ill sell the mobo, ram, processor widows as 1 then to keep it easy.

O really then why does microsoft allow activation of said OEM if you call them and tell them the situation?

Exactly! I just leave it up to them to decide, if I'm offered a phone call and the activation is successful, i'm happy, they're happy. As long as the licence is not in use on another machine it seems it will be accepted. (As regards Vista, not tried with a Win 7 licence yet...)

Even with my OEM copy of windows 7 i just told them i changed mobos and the activation guy said hang on a minute and then he reset the activation for me. Ive done this about 2 times now with Windows 7 so i don't see how OEM is bad.

Home users usually get more slack than corporate ones first of all. Second, we're not talking about reactivating windows for the same user on different hardware, we're talking about selling the computer. That is considered a license transfer, something which is not allowed for OEM/DSP licenses, if they're not accompanied by the hardware.

I'm just saying what the official terms of use are. If I was selling to someone, I would prefer to be sure that he wouldn't have any trouble with the activation.