YES, upgradiing from any OEM license to a Windows 8 Pro Upgrade from a store or from Microsoft directly WILL make your Windows 8 Pro Upgrade into a full Retail license. The Upgrade EULA supersedes your prior OEM EULA, and your prior OEM restrictions (including the restriction of transferring the OS to another computer you own) is null and void.
Source:
Microsoft Software License Agreement for Windows 8 Pro Upgrade
Website:
https://www.microsoft.com/About/Legal/EN/US/IntellectualProperty/UseTerms/Default.aspx?pf=true
[URL=http://imageshack.us/photo/my-images/46/licenseterms20130125101.png/][IMG=http://img46.imageshack.us/img46/1748/licenseterms20130125101.png][/IMG][/URL]
EULA (Page 1 and part of Page 2):
[URL=http://imageshack.us/photo/my-images/801/windoes8proupgradeeula.jpg/][IMG=http://img801.imageshack.us/img801/8992/windoes8proupgradeeula.jpg][/IMG][/URL]
MICROSOFT SOFTWARE LICENSE AGREEMENT
WINDOWS 8 PRO
(Excerpt from Page 1 & 2; Emphasis by way of ALL-CAPS is mine)
WHAT ABOUT UPGRADING THE SOFTWARE?
The software covered by this agreement is an upgrade to your existing operating system software, so the upgrade replaces the original software that you are upgrading. You do not retain any rights to the original software after you have upgraded and you may not continue to use it or transfer it in any way. THIS AGREEMENT GOVERNS YOUR RIGHTS TO USE THE UPGRADE SOFTWARE AND REPLACES THE AGREEMENT FOR THE SOFTWARE FROM WHICH YOU UPGRADED. After you complete your upgrade, additional software will be required to playback or record certain types of media, including DVDs.
CAN I TRANSFER THE SOFTWARE TO ANOTHER COMPUTER OR USER?
YOU MAY TRANSFER THE SOFTWARE TO ANOTHER COMPUTER THAT BELONGS TO YOU. You may also transfer the software (together with the license) to a computer owned by someone else if a) you are the first licensed user of the software and b) the new user agrees to the terms of this agreement. To make that transfer, you must transfer the original media, the certificate of authenticity, the product key and the proof of purchase directly to that other person, without retaining any copies of the software. You may use the backup copy we allow you to make or the media that the software came on to transfer the software. ANYTIME YOU TRANSFER THE SOFTWARE TO A NEW COMPUTER, YOU MUST REMOVE THE SOFTWARE FROM THE PRIOR COMPUTER. You may not transfer the software to share licenses between computers. You may transfer Get Genuine Windows software, Pro Pack or Media Center Pack software only together with the licensed computer.
My Personal note:
Many people on forums have assumed that the Registry Mod and the Install-Over-Install workarounds for Clean-Bare-Metal install activations are illegit hacks that violates the Windows 8 Pro Upgrade EULA. However, in reading the EULA, two things are obvious: (1) this Retail EULA supersedes the OEM EULA, and (2) the Windows 8 Pro Upgrade is transferable to a new computer/motherboard. Hence, I believe that Microsoft intentionally created a method in which clean-bare-metal installation activation can be achieved using the Windows 8 Pro Upgrade ISO.
How this method was meant to be accessed is another question: (A) End-user self-service or (B) Remote-assist by Microsoft Customer Service Agent.
So for the original question, YES, get the Upgrade, and your old OEM becomes Retail.
Seriously doubt it, but sounds like a nice experiment to see if it will activate or re-activate the license once W8 is installed and hardware changed. – Moab – 2012-11-04T20:25:58.653
Also related : http://answers.microsoft.com/en-us/windows/forum/windows_other-windows_install/how-do-i-upgrade-windows-xp7-from-oem-to-retail/21f1e8a7-8629-4a24-a576-c4eaf3a2e066 http://answers.microsoft.com/en-us/windows/forum/windows_other-windows_install/how-do-i-upgrade-windows-xp7-from-oem-to-retail/21f1e8a7-8629-4a24-a576-c4eaf3a2e066 http://answers.microsoft.com/en-us/windows/forum/windows_7-windows_install/windows-7-anytime-upgrade-from-oem-home-premium-to/1e7579ad-26be-45f4-aa33-19860ee1b34f?page=2
– AgA – 2012-12-07T19:17:53.937