On how many computers can you install Windows 10 with one key?

In order to use Windows legally, it is necessary to activate it with a license. The license is the famous serial number that we must enter during the installation or activation process to unlock all the functions of the operating system. Depending on the edition of the license (Home or Pro) it has a more or less expensive price. And also, depending on the type of it (OEM or Retail), it will be more or less expensive. But what if we have two computers? Will we have to buy two licenses or will it only work with one?

The first thing to remember is the difference between the two types of license. On the one hand, we have OEM License, cheaper than usual only sold to manufacturers. This is the one that comes by default when we buy a PC and is valid only for that PC. The Retail License is more expensive, and it is the one that any user can buy. It is not tied to any hardware, and if we change computers, we can activate it at other times.

If we are one of those who buy computers already assembled, we will have no problem, because most of them come with factory licenses (OEM). However, if we have one, two or more computers assembled by ourselves or by a store, things change. These computers usually do not have a Windows license. And that’s where the questions start.

If I have a Windows 10 key, can I use it on two or more computers?

Windows OEM licenses are only valid for specific hardware. This is related to the motherboard, and although this allows us to change some components (such as hard drive, memory and even graphics, if you can), at the time the board or CPU is changed, the license ceases to be valid. Hopefully, if we change only the CPU, we can recover it via Microsoft SAM. But if the board dies, the key dies with it.

This means that if we have an OEM license and we have activated it on one computer, it cannot be activated on another computer. However, we could take advantage of the license if we bought an identical motherboard to the one we had. But it has to be identical, even while being tested. Otherwise, it will be invalid.

Obviously, each key is unique. And therefore, we cannot activate it in any other way on other computers.