I just recently replaced my motherboard and windows said it needed to reactivate. I didn't use a microsoft account and just had a simple password on my computer. I went to troubleshoot in activation settings, said I made a hardware change, and made a new microsoft account and went to connect the account to the windows key. It said there was a problem with the activation servers and to try again later. So I tried again, and now it says it can't find any accounts linked to my windows key and doesn't let my connect an account or try again. The key is Windows 10 Pro Retail, it was a windows 7 key upgraded to windows 10 for free, and I have the key on a sticker on the case if that helps.