I was on an airplane and my phone died, so I turned on my ibook to charge it (not plugged in) things were working fine but noticeably sluggish. Eventually word froze, so i turned the iBook off. I tried to turn it back on (no iphone plugged in) but it got stuck on a gray screen, blue screen, apple screen, login screen...etc... there was no consistency, just that it wouldn't start.

Later I plugged it in and tried all the diff resets, and safe mode..nothing worked except after cmnd-option-p-r it turned on. once. It was still very sluggish and froze quickly. That reset hasn't worked again, and now every time i try to turn it on it will get the gray screen, no variation. Keep in mind all of this has been within the last 2 hours.

Another thing i noticed is the light on the power adapter will just randomly just go off (also a new development), but nothing happens when it does. I've tried all the steps with just the battery in the machine to make sure it wasn't the power adapter.

specs: iBook G4 12' 800mhz on 10.4.11

Tried to boot on your OS X DVD and check your hard disk with Disk Utility ?

Also, can you explain how your phone died and how do you know it ?

I had to track down a disc to borrow as mine's far away at the moment, but I ran disk utility (off Leopard disc...but disk utility is disk utility right?), it didnt find any problems. Since then I've been starting my computer up every 10 or so minutes, the last time it got past the grey screen, but took 30 minutes to finish booting, and the desktop is all there, the cursor moves, the screensaver runs if i leave it be for awhile but the machine is unresponsive if i click on anything (sometimes if I click and wait 5 or so minutes what I clicked will begin to run or a menu will pop up, but I won't be able to click that.) I can't even browse through finder.

...as for my phone, by 'died' i just mean the battery ran out.

If you boot on the Install DVD, do you encounter the same problem ?

You can also boot with SHIFT key pressed until you arrive to the Login window (it will disable extensions).

shift was one of the first things I tried, never got me as far as the login window.

I can boot to the dvd/install options just fine, I also booted in target disc mode successfully and all my files seem intact.

When I tilt the ibook during startup it makes noticeably different whirring noises, I guess this could be the fan but i want to mention everything I can.

I guess the noises are generated by the fan or the hard disk.

Can you try to reinstall the 10.4.11 Combo update ?
I think something went wrong with your system.

If it doesn't solve the problem, try to boot in single user (Apple + S) and check the disk by typing:

You can also install AppleJack and use it in single user boot as well.
(this tool will cleanup and repair most of the problems)

Another thing is to move out the apps located in /Library/StartupItems
(one of them might be responsible for your problem).

Try all of these steps and if it doesn't solve your problem, we'll see what we can do later.

on my most recent attempt to start up I just got a message saying "invalid memory access at #####etc"

welcome to open firmware, i typed mac-boot...computer is still stuck on grey

how can I re-install 10.4.11?

Can you target boot from another PowerPC Mac and reinstall the combo update on your disk ?