Windows
Windows
Kinguin/G2A, though often unreliable. Official copies exist, but you're likely downloading pirated versions since they're usually OEM keys. You're not buying the software itself, just the permission to use it as per the license terms. These keys were meant solely for assemblers and server makers, so the license is void if you claim ownership. Even though the key will work in Windows, you're still getting nothing because the agreement doesn't apply to you. Pirate users face the same issue—they lack a valid license, so they can't legally use the software. They might run Windows and "activate" it, but without a proper license, that's not valid. This is why such deals are completely wasteful—wasting money without any legal standing. (not my quote)
Best Buy, Amazon, and Newegg offer OEM keys too. OEM is intended for system builders broadly, including the consumer market.
Legally obtained Windows licenses. We focus on building systems, not just trading keys from various sources like Gamesdeal, G2A, Kinguin, etc. These could come from MSDN, stolen COAs, refurbishers, etc. On the other hand, platforms such as Newegg, Amazon, and Best Buy sell keys from trusted vendors (like Microsoft) at prices close to the genuine market rate.
Just set up Windows and avoid entering the activation code, but it's unclear how long it will remain valid without one.
It really functions indefinitely, doesn't it? You just miss out on a few capabilities and can't tailor it, but it doesn't completely restrict you.