Restart Message on iBook

[DaisyLil]

My 2005 iBook G4 is running on OS X without any additional RAM or any connected devices such as printers etc. I was using safari when the panic "restart your computer" message popped up. I restarted, but the message appeared again before i got past the gray screen. I rebooted a number of times, getting to various stages of setup before the message appeared. I left it over night and tried again this morning and everything seemed to be fine again, but after about 15 minutes the message reappeared. I've tried resetting the PRAM and PMU but so far no good.
Any ideas?

 

[karazelle]

It seems you have done everything you can.

My only final tip would be to try to "reseat" your RAM by opening the cover where it is, take it out, then put it back in and see if it helps. Also, listen to sounds from the harddrive.

And finally, attempt to boot with the MacOS X DVD that came with your laptop * and holding down the letter "c" after the chime. You should get the option to run diagnostics.

* - meaning, if your laptop came with Tiger and you bought Leopard as an upgrade, you need to use the Tiger DVD, i.e. the DVD that was bundled with your Mac.