You can buy a used mini PC for less than the price of a new Windows 11 license. I know there are cheaper license sites out there (unclear how legit they are) but this way you get a Windows license and a spare PC to run Linux!
There could be a bit of a caveat here. I when I purchased my laptop it had windows 10 installed. When I installed Mint, I could not reuse that key in a VM because it was “different hardware”. The license, could not be transferred under any circumstance. I had also purchased the upgrade to Pro through the windows store. That’s also lost.
I seldom run windows, even in the VM, but it still leaves one a bit bitter.
Usually calling Windows support, they'll give you a key if you just tell them you replaced some piece of hardware due to failure, assuming you haven't been transferring the same key around for awhile. They tend to be more invested in keeping you in the Windows ecosystem than they are are just getting one more license sold.
I called support, they said no. Asked for a one time exception, still no. The key to my knowledge was only used once on the laptop when I bought it new.
I reused a Win10 Pro key from a mini PC from 2015 onto a brand new build and it worked right away. Not sure what the difference is with your situation. Maybe it was your license type?
When I build a new PC, I could not transfer my old 7 pro retail license, even though it worked fine on my old PC running Windows 10 and it even said it was a digital license connected to my MS account.
So I bought a Win 10 pro key from one of the ebay resellers aber everything was fine... until it wasn't.
I updated the firmware for my mainboard and Windows took that for a replacement of hardware. Troubleshooter did not show three option "I recently changed my hardware" and did not give me the option to call Microsoft's support.
Turns out it was a "one time install" key which was invalidated by changing the hardware. So it couldn't activate a second time. And since the key seller was out of business at that time (they'll change accounts every few months), I had no way of getting the key replaced.
Luckily, I still had an old Windows 7 COA with key and CD lying around from an old Dell business Workstation. That activated just fine.
But yeah, even if you have a valid license connected to your Microsoft account, there's no way of seeing it in your account, and it's not guaranteed MS will honor it.
It is my understanding that this can only be used to run the OEM license one one instance in a VM, on the specific hardware that is originally licensed. IE, you virtualize the license if the bootOS is Linux, but you can't run 2 instances of the same windows license inside each other.
Cheap license sites (windows, games, etc) usually use keys bought via stolen credit cards. Pirating it is much better than buying from those sites, including for the devs that get punished for chargebacks from those keys.
Tbh if you want gray area keys. Microsoftsoftwareswap has always had verified users selling business generated licenses keys. If you HAVE to buy a key, at least buy one from vetted people and not some rando on a seller site
The answer is a resounding maybe. If you activated with a Microsoft account or if there's a TPM chip, the chances of it still working increases. There are different kinds of licenses, but if it fails, there's a better than not chance calling MS support and just telling them you had a hardware failure on your laptop and you need to reinstall, they'll get you going. Not a guarantee though. And I'll caveat and say this information is a couple years old (I don't work in tech support anymore).
They cost like $5 online, it's not like it's a huge risk. I've bought OEM keys before and they work fine. Just use a credit card so you can easily get a refund if it's fake.