ibook tries to boot up?

Hello

I have a ibook g4, 1.0 ghz, 512mb ram, 30 gig hd. My problem is that that the Ibook tries to boot up, the apple and twirling thing are both on the screen but after a minute or two the ibook shuts off. Onyx was showing that there was something wrong with the start up disk, so I put the install disk in to get to disk utility and ever since then the notebook is on the blink. I never could get to the disk utility. I've done something wrong?

laughing gravy

I think your hard drive is dying, newegg.com have good prices for replacements.