New
#1
New motherboard replacement - identical to the old one - OEM Win10 SL
This PC isn't mine, it's my co-worker's at home. He is a complete newbie, so he never attached his Microsoft account.
The motherboard was replaced with a completely identical type by the vendor, the old one kaput, as it's a HP Pavilion PC (still under warranty). Problem is the Windows is now unactivated and complains no CD Key installed.
What now?