Hold down the Power button for several seconds or press the restart button."

This message, in English, French, German and what appears to be Japanese come up in a gray box on my daughters G4 iBook when she tries to start it. Once it appears (after her desktop loads and dims out) no keys or the trackpad operate. It sure doesn't look or sound like an Apple kind of message at all but who knows.

She has "misplaced" her system disks so a CD start-up is not feasible at this time.

Any suggestions would be greatly appreciated.

That's the mac version of the blue screen of death. Usually a hardware problem.

Try reseating the RAM. Maybe the RAM chips became loose. While the power is off (battery removed) pull out the RAM stick and put it back in. If there is an airport card pull that out and put it back in. These are just general instructions, I'm not familiar with a G4 iBook and it's internals (if there are RAM chips that can be removed, etc.)

From Apple:

What is a kernel panic? (Mac OS X)

Thanks to you both. I am off and away to try to solve a kernel panic problem (which I had read about but never experienced).

Thanks again. I will post the results of my efforts.

I haven't had a kernel panic recently, but if I remember correctly, I used one or both of these options:

Reboot holding Command + S to start in Single User Mode
Type "/sbin/fsck -fy" without "", then hit Return
Once your drive is checked, type "reboot" without "", then hit Return

Reboot holding Command + Option + O = F to start in Open Firmware Mode
Type "reset-nvram" without "", then hit Return
Type "reset-all" without "", then hit Return

You may not need to type at all, depending on your Mac model:
http://support.apple.com/kb/HT1379

Make sure that no application, preference, etc., is causing the panic. Did you install something before the Panic started to occur?

As always, what has worked for some people may not work for all people. Best of luck.