Invalid B-tree Node Size?? Please help me

I managed to break my ibook G4 royally the other day, put the ibook on my desk next to a small fridge magnet not even realising it was there a minute later the hard drive was making awful noises and the whole thing crashed. I turned the ibook off, saw and removed the magnet from the area, but now when i turn the ibook on it never gets past the part of the little folder that flashes with a ? and mac symbol. Hv tried reinstalling OS X but when it comes up with select destination there is nothing there, have tried disc utility and it comes up with an error "Invalid B-Tree Node size" disc utility wont repair it. At the moment i dont know what to do, can i fix the problem any way please advise

Looks like you'll need a new harddrive.

Have you ran the hardware test CD that you should have got with the ibook ? This may tell you what the problem is, either that or Techtool pro ?

Iv tried to run the hardware test buy putting the restore disc in and holding option during startup but it freezes and i havn't been able to use it, i had techtool pro installed on the computer but cant find the disc for it so thats a dead end, have read in other forums that diskwarrior can fix b-tree node problems but havent read it officially does anyone have any experience with discwarrior

Yes, diskwarrior is one of the few programs that can do that and is a good program. But if you can't get it to boot up from the CD or if the harddrive is broke then it's not going to help anyway. If you have got a spear harddrive it maybe an option to take the thing apart and try booting with it to see if it's only a problem with the HD.

Have you got an OS9 classic system CD ? Maybe you could try booting and reinstalling with that ? If it's possible (it's not with my imacG5 as it will only boot with OSX, not sure about the ibook G4's)

Could also try going into the open firmware at start-up, but i don't have any experience of doing that but have read about it in the past. Try doing a search at http://www.macosxhints.com/index.php or have a look at www.macfixit.com

Right, thanks for your advice, i dont have an OS9 disk but i think it is included on my installation disks, No i dont have a spare hard drive. How do you mean by boot up, the computer starts with the disk in and i hold down c so it launches the cd that much works but when it comes to select destination for MacOSX to install there is nothing visible. Does Diskwarrior run from your desktop as such or can you run it from startup again holding c. thankyou for your help. Oh i cant startup up in single user mode or verbose mode.

Yes, diskwarrior runs from the CD in the same way as the MAC OSX CD and you can also install it onto your harddrive (running from the CD is better and I believe has more options).

By 'boot up' i mean starting the computer.

If you can start up from the CD and it all works, apart from not being able to find your harddrive, then I should think that your harddrive is damaged and will need replacing. Which isn't all that bad as they are not too expensive. It could also be something else but I can't imagine anything else being so effected by a fridge magnet where as a harddrive has moving parts so it's possible.

Thanks alot for your help, now i need to decide whether i risk it and buy diskwarrior to try and recover my files or just buy a new hard drive. And lose alot of time and effort more than anything. Going away for a week on saturday so will tackle that problem when im back and see how much money i have left. Again thanks alot for your help and to any one reading this beware of the magnets!

I had the same problem when I was upgrading to Tiger. Not matter what I did it didn't want to load Tiger.
I found a solution for it though.
All you need is another mac computer with a firewire cable and on the busted computer press T when you turn it on, on the other computer wipe the drive and click on the partition and delete it.
After that, you can reinstall the OS again.

Hope this helps.