I have a headless old PC which I used to connected as Admin user with my name instead administrator. But now
I forget my password, but fortunatly I do have the password saved on my Linux PC so I can still login from  my
Linux PC. But still, I don't know how to change/reveal my own admin password. Is there some easy way or
reliable software to do that?

PS: I do write my password on my notebook as I usually do, but for some reason, it's not the right one, or
I misread my own writing, which happens often, but I will keep trying.