I've sent some messages on the tech-support channel, but the only answer I got there is "you should know the password, bro", which is impossible, bc the pc doesn't have a password. I've even tried every password I used for the last years and that did not work + blank password also doesn't work.That just shows up on boot for no reason and I have no idea how to solve it.
I'd be fine with a new installation, mostly bc there is nothing on that pc. So any boot reset or anything like that is totally fine, I just want a way to use the pc.