Resetting Serial number after motherboard (or BIOS) change

[freeagent]

I decided to go ahead with the motherboard replacement on my T520.

I saw something in the manual about resetting the serial number. How important is that?

Same thought about the OEM Windows 7 and 10. It will look to MS like I have a new machine (or the one the MB came from. Do I need to do anything to correct that?

[TPFanatic]

My expectation is Microsoft will reactivate you with the phone service and/or the windows 7 key on the bottom of the laptop. I would try to activate first and see what happens.

[RealBlackStuff]

You can change the TYpe, S/N and others using this HMD program: https://download.lenovo.com/ibmdl/pub/p ... tm38us.exe
When you run this first time, it unpacks into a folder.
In that folder you find installing information.txt for making a self-booting USB-stick with which you can run most Thinkpads, incl. the T520.
With that you can then change the BIOS data back to the 'old' mobo info (if you made a note of that, or from the label on the laptop bottom.)

[freeagent]

My expectation is Microsoft will reactivate you with the phone service and/or the windows 7 key on the bottom of the laptop. I would try to activate first and see what happens.

I think I posted this elsewhere, but in the end all I had to do was as you suggested - Just entered the key. This worked, I believe because I had W10 activated on my MS account. This with my existing W10 - no need to re-install. I didn't change the model/SN in BIOS, but Windows picked the new ones up in activation process.

I am almost back to square one Still on old BIOS version, for now.