Power Mac G5
I JUST bought uesd power Mac G5, I missing get administrator password by owner how login
Powerbook
If you have a retail install-restore DVD system disc set, that can be used to start the Mac
and then erase the hard drive; if you haven't the other application install software, that
is something to consider along with the process of learning how to use Mac OS X 10.5.8.
The retail version Leopard 10.5 DVD install-restore DVD can start & run the Mac.
This will allow you to use one of the primary re-set admin password methods.
• Mac OS X (10.6 and before) - Resetting a Forgotten Account Password:
https://kb.wisc.edu/helpdesk/page.php?id=3853
And if you didn't actually acquire a G5 PowerPC (a mis-identified early 'Mac Pro' tower has
similar look, but utilizes Intel-based hardware and different software) that's another detail.
There are some things you could try to 'reset admin password' without the install DVD media.
Each of the main ones are somewhat covered; and may overlap to a degree...
•Five Ways to Reset a Lost Administrator Password - TidBITS:
https://tidbits.com/2014/01/17/five-ways-to-reset-a-lost-administrator-password/