[Dailyplanet]

Hey guys,
Recently I've been hearing these weird whirring noises from my iBook. Sure enough, one day the noice wouldn't stop and when I restarted the computer it wouldn't boot OS X. I got as far as the blue screen before the "Starting Mac OS X" window comes on. Oddly enough though, I was able to boot Unbuntu off of it. Any ideas as to what's going on or how I can fix this?

[imitchellg5]

Try single user mode first. Boot up and hold down the S key. If that doesn't work the logic board is bad.

[wataru]

Uh, what? If it can boot Ubuntu but not OS X, then how do you jump to the conclusion that the logic board is bad? The logical assumption is that either his OS X install is hosed, so he should reinstall, or at worst that his hard drive has a physical problem.

And it's command-s at startup, not just s.

[Dailyplanet]

What is the purpose of single user mode?
p.s. It's she, not he

[wataru]

It's to minimally boot OS X. It is not some built-in diagnostic mode independent of a hard drive-based OS X installation.

[profetes]

Also try uninstalling and reinstalling OS X. Reinstall it by using the osx dvd by holding command C at startup with the dvd in the drive.

[lilford]

Also you could try booting off of an external hard drive. Sometimes this helps people whos computers don't boot into OSX. If that doesn't help and nothing else you try has worked, then yes, the logic board is shot. In that case if your ibook is still under warrenty, then take it back to apple and see if they can repair/replace it for you. If apple won't help you fix it, then try taking it a 3rd party repair place and see if they can help you out.