powerbook freezes during startup

[ScottySo]

last night I tried to shut down my powerbook. it closed all open programs and went to the the blue screen with the apple logo, and the mouse cursor turns into a swirling dotted circle. it usually stays here for a few seconds and then shuts off. but this time it stayed here for about 10 mins before I just held the power button to force it to shutdown.

this morning I wake up and try to start up and it goes to that screen (again it should only be here for seconds) and it won't go past it. Any help or advise is really appreciated.

I did try some googling but coudln't find anything. I am sort of terrible at this sort of thing.