Built-in administrator account reset its password

Yes I wasn't entirely clear either, I was thanking you for confirming that it should not normally be possible.

All right, a little update. I showed my PC to a professional and he managed to unlock it and give my back my rights with some IT magic. He also disabled the built-in admin account, which I previously wasn't able to do. So all is well for the time being. It's still a huge mystery to me how the admin account reset its password, and what the password was. I guess human error on my part can't be completely ruled out.

Thank you for all your suggestions, and for taking the time to help me out!

Espe said:

I guess human error on my part can't be completely ruled out.

Glad to hear you've got it working now. I make it a practice on all my machines to create a second local account and make it an administrator, a useful way back in for such 'emergencies'.