lost G4 password
I need some files from my long-neglected G4. (I tried using target mode to get the info, but there are four internal drives, and only the first one shows up.)
Needless to say, I don't remember the password (I'll never forget this!), and it is not in my voluminous lists of old PWs.
On top of that, I can't find an older OS X install disk, so I can rewrite (or eliminate) the password. What can I do?
MacBook Pro, OS X El Capitan (10.11), 3 GHz core duo, 8GB RAM