Got an old iMac 9.1 running OSX Lepoard in. Client needed the password reset on it, but had long forgotten it and didn’t have the Apple account it was bound to.
1. Boot into single user mode (press Command-S at power on). It’s bassically just a command line (like DOS for you PC users)
2. Type fsck -fy
3. Type mount -uw /
4. Type launchctl load /System/Library/LaunchDaemons/com.apple.DirectoryServices.plist
5. Type dscl . -passwd /Users/username password, replacing username with the targeted user and password with the desired password.
6. Type exit