Yes, an operating system can be used multiple times even if it indicates only one copy is needed.
Yes, an operating system can be used multiple times even if it indicates only one copy is needed.
Without master disk (if unavailable), use once per license/CD for Windows 7, 8, and 10.
They won't work together at the same time. My previous response clarified that. The store policy allows only one device at once, so it's not allowed legally.
No one would ever buy it, and it's no longer available for sale
On the same machine you can apply the license as many times as needed. If the motherboard is replaced, it will be treated as a different system. At that stage the license variation becomes relevant. There are three primary categories (excluding enterprise): RETAIL, OEM and branded OEM. From these OEMs they become enabled on the initial motherboard. However, based on my experience up to Windows 7 you could swap the motherboard and retain the OEM key, while branded OEM became restricted after Vista and later versions. RETAIL remains adaptable even when the motherboard changes. Keep in mind that applying OEM keys to another board violates the license rules, and seeking clarification on this matter is prohibited on official forums.