"The free Windows 10 license works very differently from previous Windows licensing systems. These all required a product key. Even modern Windows 8 and 8.1 PCs ó and new PCs that come with Windows 10 ó have a Windows product key embedded in their UEFI firmware. If you buy a new copy of Windows 10 ó for example, to install it on a PC youíre building yourself ó youíll also have a product key.
In this case, the product key would always serve to activate Windows. But Microsoft hasnít been handing out Windows 10 product keys to upgraders. Thereís no way to find your Windows 10 product key if youíve upgraded for free ó you just donít have one."
Also: "Embedded in your PCís UEFI firmware: Many newer PCs that come with Windows 8 or later use a new method. The key for the version of Windows the PC comes with is stored in the computerís UEFI firmware or BIOS. You donít even need to know it ó assuming youíre installing the same edition of Windows the PC came with, it should automatically activate and work without you needing to enter a key. Itíll all happen automatically."
Regarding the OP's question, it seems he may still be able to use his original Win10. When reinstalling, he has to skip past all references to registration or activation and the install will proceed. When completed he'll have to phone MS and explain that this isn't a new computer with a second install but his one and only. Then he should be OK. Allegedly. MS are still very coy about all this. LOL.
Have you notice the OP is using a Windows 10 Technical Preview, so what license is there for a Technical Preview ?
May I ask why some are assuming he`s talking about Windows 10 ?
If he`s running the TP, he doesn`t even have a license for 10 so........
I`m under the assumption he`s talking about a license for 7, 8 or 8.1 as he does not mention, and yes I know he`s using Tenforms.
The only time I know of when an OS auto activated to a certain manufacturer`s pc is when you used the oem disc that came with the PC, I beleieve XP did it, Vista, maybe 7.
8 is when they started putting the key in the bios, whether they gave you a disc I don`t know, I would never buy a Windows 8 or 8.1 machine, not no way, not no how.