How do I totally remove the 'ghost' of mountain lion from my ibook G4? I erased and restored to panther then Snow Leopard but ML still causing problems

Question

I am not very tech savvy but work from home and have used Macs for about 18 years, so know the basics. Have had iBook G4 for almost 5 years, it came with Panther Discs and later added Snow Leopard. Never had even the slightest issue until about 2 months ago. Kept getting "browser no longer supported" on websites and eventually could no longer edit my own Jimdo website or publish on YUDU, so downloaded Mountain Lion and installed it on my iBook.
Straight away it was much slower to start up,  wasn't that keen generally, but used it for 6 weeks hoping I would get used to it. At that point my older Mac Mini (also running on Snow Leopard) died and as I wanted to continue using my printer and scanner (neither had drivers to work with Mountain Lion) I went to Time machine and restored my iBook to the day before I installed Mountain Lion.
iBook was better immediately and started faster again, everything fine for about 3 weeks and then last wednesday my iBook would not come back on. The grey start up window showed the apple and whirly wheel for between 5 to 10 minutes, then just a blank blue screen. I could move the cursor but that was it. Tried to start up again many times, eventually the grey apple was taking up to 15 minutes before the blue screen. Refused to go beyond that blank blue screen when holding down C and starting up from either Panther or Snow Leopard discs or from Disk warrior disc. Disc Warrior and Utilities said nothing was wrong with the hard drive but always showed the HD icon with a yellow exclamation sign over it.
Because of work pressure, after 48 hours with no improvement, I wound up buying a new iMac, so can work but still would love to have my iBook back, plus use of my Printer and scanner again. Last night finally managed to Panther reinstalled after erasing 4 times and many failed attempts at install. Everything seemingly fine but Snow Leopard first reinstall failed so erased once more. Second time SL installed but gave a warning in red saying something to the effect that as I am installing an older OS over a newer one, there will be issues. This leads me to believe that somehow, despite Time Machines and now 5 separate Hard Drive erasures through utilities, Mountain Lion is STILL on there? How on earth can I get rid of it and return just to Snow leopard. Any help really welcomed as I am at the end of my tether but don't want to give up on my old faithful (until now) iBook
PS: Sorry if I post in the wrong section

Answer 1

First, that cannot be an iBook G4 as that machine cannot run Snow Leopard let alone Mountain Lion.  To run Snow Leopard it has to be an Intel processor, not a G4.  What does it show as the Model Identifier in About This Mac, More Info, System Report, Hardware, Model Identifier?
Second, if you have erased the hard drive there should not be remnants of any prior content.  Even though Disk Warrior is saying nothing is wrong with the hard drive, it sounds as though there are problems.  You may want to consider simply replacing the hard drive so there are no questions about faults.  A good source is OWC, http://www.macsales.com where they also have on-line videos showing how to do the replacement.
Third, you could also try again to restart using the Snow Leopard DVD/CD and use Disk Utility on that install disk to erase again, and do it a couple times, then try to install.  If it continues to refuse, then it sounds as though there is a fault with the hard drive.