How does Microsoft validate OS keys?

[tareyza]

So, I recently took out my hard drive and got a fresh win 7 iso and did a fresh installation of the OS on my SSD. Out of curiosity though, how does microsoft validate that the OS isn't on a new computer? For example, what if I plugged my hard drive into a separate computer, would I now have 2 different computers with 1 license of windows? And, what if I put my SSD into another system? I'm curious as to how Microsoft manages this. 

[WinNut]

Microsoft, from what I know, writes the OS key into the BIOS so that if you try to boot it on a different computer it'll become deactivated.

[ManIkWeet]

I believe it uses your motherboard as validation. It definately does not write the key into the BIOS as stated above, too much chance of corrupting the BIOS that way.

Basically it takes some hardware ID of your motherboard, that's why all Linus' testbench videos don't have a legitimate Windows installation.

[zonahbear]

Microsoft, from what I know, writes the OS key into the BIOS so that if you try to boot it on a different computer it'll become deactivated.

But how does the BIOS know it's on a different machine?

[JeffreyEagan]

Microsoft, from what I know, writes the OS key into the BIOS so that if you try to boot it on a different computer it'll become deactivated.

That's with OEM keys.

[JeffreyEagan]

Microsoft uses a system called KMS management. Basically, when you enter your key, it uploads it to the KMS server, then the server returns data saying that the machine is now activated. Now when Windows Activation Technology is downloaded to your system through Windows update, it'll see that you've got a legit key, backcheck it with the KMS server, then if everything checks out, it just sits there dormant. I think it runs once every startup.

[ChaseB]

How can Linus Legal have corrupted keys 

[ManIkWeet]

How can Linus Legal have corrupted keys

Continuously swapping motherboards... you know to test them and stuff.

(Yes, his SSD is full of driver junk, and benchmark programs)

[Master Disaster]

Microsoft uses a system called KMS management. Basically, when you enter your key, it uploads it to the KMS server, then the server returns data saying that the machine is now activated. Now when Windows Activation Technology is downloaded to your system through Windows update, it'll see that you've got a legit key, backcheck it with the KMS server, then if everything checks out, it just sits there dormant. I think it runs once every startup.

Nope, only large businesses can get VLKs and use KMS, home users can't legally use the service.

In a home situation it takes a hash from your BIOS image (exactly like an MD5 sum) then uses that to create a user ID, that ID number is then tied to your key during activation. That way if the board changes so does the BIOS hash and the user ID meaning both Windows and MS know its a different computer.

[JeffreyEagan]

Nope, only large businesses can get VLKs and use KMS, home users can't legally use the service.

In a home situation it takes a hash from your BIOS image (exactly like an MD5 sum) then uses that to create a user ID, that ID number is then tied to your key during activation. That way if the board changes so does the BIOS hash and the user ID meaning both Windows and MS know its a different computer.

Since you seem to know about this, I've got win8.1, not an OEM copy, lets say i wanted to move it to another system and deregister this PC, do I simply just enter the key on a new system or do i have to call MS first to have the key deactivated?

[Master Disaster]

If its retail then you can 'transfer' the licence by using it on a second machine, trying to activate (which will fail) then selecting phone activation, ringing the phone activation line and telling them you want to move the licence to another motherboard.

They'll reactivate the key to the new machine, give you a code to type in to the activation wizard and deactivate the old machine.

Once its done its irreversible and any future activations on the new machine will be handled without having to ring MS.

You cannot transfer OEM licenses at all, they'll refuse to do it if you try.

[Ceatra]

But how does the BIOS know it's on a different machine?

The BIOS is on the Motherboard not on the HDD/SSD

[JeffreyEagan]

If its retail then you can 'transfer' the licence by using it on a second machine, trying to activate (which will fail) then selecting phone activation, ringing the phone activation line and telling them you want to move the licence to another motherboard.

They'll reactivate the key to the new machine, give you a code to type in to the activation wizard and deactivate the old machine.

Once its done its irreversible and any future activations on the new machine will be handled without having to ring MS.

You cannot transfer OEM licenses at all, they'll refuse to do it if you try.

Thanks!