When i try to turn on my ibook g4 with os X.4 all i get is the gray screen that shows the apple pic and the loading spinny thing. i had the day before connected to my freinds network, only to access the internet, downloaded a bit of stuff and then went away. when i tried to turn on my ibook the gray screen is as far as it gets. i left it on for a few hours because its making sounds like it is loading but it won't go any where. i tried holding the apple key, optoin and P and R keys to reset the preferences but that only resets the computer and starts it all over again. some help wold be really nice, i'm also new to macs so i don't really know how they work underneath.