iBook won't boot anymore.. =(

I get a message saying "You must restart your computer." (hold down the power key, blah blah).

I've researched a little bit, and apparently its indicative of a kernel panic.

I cannot get it to go past this point. HELP ME (please, I'm stressing out over here!!). It's not booting from CD either.... what's going on?

(This happened for the first time after I installed the latest updates [for 10.4])
Thanks in advance for any suggestions!!

yellow said:

Have you put in 3rd party RAM? At what point does it kernel panic? And just to be sure, you've tried to restart and boot from the installer DVD and it kernel panics again?

Click to expand...

No RAM or anything has been changed, its all OEM.
And it happens like this...

I get the Apple logo, the sound, the pinwheel, then it goes to a black screen and then I get the (presumably kernel panic) message.

And ya, I've tried booting directly from the installer DVD...

I managed to boot into single user mode, and ran FSCK /yf.

It fixed it!!!