Windows – OEM Windows 7 key with downloaded ISO

According to Microsoft, an Windows 8 Key provided from am OEM is not transferrable:

Q: My customer bought a new PC and wants to move the OEM software from the old PC to the new one. Can't users do whatever they want with their software?

A: No, the OEM software is licensed with the computer system on which it was originally installed and is tied to that original machine. OEM licenses are single-use licenses that cannot be installed on more than one computer system, even if the original machine is no longer in use. The End User Software License Terms, which the end user must accept before using the software, state that the license may not be shared, transferred to, or used concurrently on different computers

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That's the legalese behind it. As far as technically, can you do it, Windows 8 OEM licenses seem to be tied to hardware hashes that include the motherboard:

manufacturers will be required to write a unique Windows product key -- which is associated with the hardware hash -- into the system's BIOS

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So no, it would appear that even with the original OEM key and installation media, the key is bound to the hardware it is installed on.

You should be able to use any unbranded OEM copy of Windows XP (i.e. not Dell, HP, Gateway, etc.) to reinstall Windows XP Professional using the product key from the sticker on the bottom of the laptop.

Note that you need to use an OEM disc, not a Retail or VL (volume license) disc.

For your purposes, there is no difference between Windows XP, and Windows XP with Service Pack 1, 2 or 3, though for security reasons you should install a copy of XP which includes Service Pack 3 before connecting the computer to the Internet.

The only thing is that you may have to activate Windows by phone, as online activation was disabled for OEM product key stickers several years back. Since XP has gone end of life, OEM product keys can be activated over the Internet again.