Wont start up

My friend has an old G3 ibook and when it starts up it freezes at the white screen that has the apple on it and the grey circle. He's tried a few different methods (cant remember which) but cant get it started up. Could anybody list some good methods to fixing the problem?

go through this llist first, the sticky on the operating system section: http://www.mac-forums.com/forums/showthread.php?t=5284