I work in IT, and today I got a broke powerbook g4 placed on my desk. Thing had been dropped. Turns on fine. But sits at what I think is the mac load screen(apple with a pin wheel spinning below it). I know how to take the harddrive out(found a guide online) However, ive never used a mac. So how do I get to the boot menu and all that(bios type stuff). And what will I need to do to get a new OS on the machine>? Just the discs that should have come with it>? Basically i need a lil course on how to use mac stuff when first booting and how to get an OS on. Any built in dianostics i can run to make sure its a harddrive? Thanks for any links or help.