Mac Forums

I have a MAC iBook G4. It has been months since I restarted and last week I did. stupid me, I forgot the password and cannot find the cds. I tried to be smart and found a forum that gave directions on what to do by pressing Apple + s and enter in commands. I entered exactly as I read and now my computer is no longer loading the main log in screen. the grey loading screen with the Apple appears. it'll load for a good 3 min than restart itself to the same loading screen to which it will than restart itself. it did this for 25 min until I gave up and turned it off. what have I done! can I fix this?