My son has an old ibook G4 (2004) that suddenly stopped running yesterday while he was taking notes in class. If we press the power button, the fan starts up noisily, but it won't boot.

It turns off intermittently if I hold the power button down for 10 seconds, but often won't turn off. In that case, I can make it turn off by holding down shift-cntrl-option (I think) and pushing the power button. By firmly pressing on the left hand side of the case, we got it to start to boot up. But then it shut off.

Any hope of getting his files off this machine?

Try running with just the battery, or just the plug and no battery installed to see if any combo of these things will work

Thanks, seahwk.

Unfortunately, that didn't work. We were able to start it up by having my son push down on the left hand side of the case. I backed up to an external drive. I am trying to run disk utilities even though it seems like a hardware problem.

I would not have thought of pressing on the case like that, but someone at the apple discussion website reported last year that it had worked for him, so we tried it and it works! Very weird. My son had to press so hard, his hand hurt though. I reset the PRAM and the fan noise is now gone. Hopefully, that's a good sign...

Hopefully that's it, just make interval backups, laptop may be on last leg, better safe than lose data/files etc..