Deleting File in Single-User Mode?

Well, It seems I fixed one of my problems with my G4, but now I have another. Ever since I went to update my software, my mac seems to get hung at the "Login Window starting" screen. I've searched around for what seems to be a simple fix by booting in safe-mode and deleting the /Library/Preferences/com.apple.loginwindow.plist file, but it's not easy. And that's because the login window starting screen is hung in safe-mode too. So, I was wondering, is it possible to delete this file in single-user mode, or firmware, or whatever? What's the command for it? Help!?

rm /Library/Preferences yada yada yada

If that doesn't erase it use

sudo rm /Library yada yada yada and it will ask you for your admin password

Where would I type that? Is there something I can type up that'll make it so it auto-logs into my account?

You type that in single user mode

It doesn't ask for password, and just copies what I wrote, and puts a question mark after it.