IMac G3 freezing after changing startup disk?

Question

Hello.
I bought a iMac G3 I few months ago just for a hobby and have been playing around on it.
This morning I noticed two other previous system folders in the system folder.
I then opened "startup disk" (I think that is the name) and chose to restart with "Previous system folder".
When it re-booted it opened up differently, had a new background and made sound effects when clicking and scrolling.
I decided to change the startup disc to "Previous system folder1" (which is the other previous system folder)
This time when restarting it booted normally until the desktop icons loaded. The mouse and keyboard froze and then a message popped up saying "To use your internal modem you need to select the country from where you will be using your computer". I try to use the mouse and keyboard to select, "Australia" and then "OK" but as previously started the mouse and keyboard are frozen.
When booting up I can use the mouse and keyboard on the loading screen until it freezes when the desktop appears.
(The computer was working amazingly before I stupidly changed the system folder)
Why is this happening. How do I return to a previous system folder when it keeps freezing.
Here is a youtube video showing you what happens:
https://www.youtube.com/watch?v=uYURgG2W5x4
Please note, I do have all the software CD that came with computer, however for some reason discs won't work on the computer they are unrecognizable.
All keyboard commands do nothing for example holding down shift into safe mode still freezes.
Thanks in advance!
Stewart

Answer 1

I'm not sure what OS you are running here.
There is a way to set what os  boots from the firmware.  Not sure how.   Look tomorrow.  let me know via another post.
For classic, you could try hold the
space bar
then booting. or is it the shift key?
If this is a slot loader, try:
The startup manager will list all of your bootable partitions then give you a choice of which to boot.  Hold down the option key then power on. Continue holding down the option key until you see the startup manager. This brings up the startup manager. Click on your hd or disc. Click on right arrow key.
Restore Tiger 10.4 & Leopard 10.5  DVDs are available from Apple by calling  1(800) 275-2273. Have your serial number ready. Have your credit card ready too.  There may be a small fee.
https://discussions.apple.com/thread/4720126?tstart=0  -- January 20,2013
https://discussions.apple.com/message/24588313#24588313 -- January 22,2014
gical Macintosh Key Sequences
http://davespicks.com/writing/programming/mackeys.html
http://davespicks.com/writing/programming/mackeys.pdf
Mac OS X keyboard shortcuts
http://support.apple.com/kb/HT1343
Startup keys
http://macs.about.com/od/macoperatingsystems/qt/osxstartupkeys.htm
I have a list of magical boot key sequences:
    Key Combinations-- Effect
    * mouse down -- Eject removable media ( I think Boot ROMs prior to 2.4f1 excluded the CD drive )
    * opt -- Bring up OF system picker on New World machines. 
             iMac g3 400 or newer machine
    * cmd-opt -- Hold down until 2nd chime, will boot into Mac OS 9 ?
    * cmd-x (or just x?) -- Will boot into Mac OS X if 9 and X are on the same partition and that's the partition you're booting from.
    * cmd-opt-shift-delete -- Bypass startup drive and boot from external (or CD). This actually forces the system to NOT load the driver for the default volume, which has the side effect mentioned above. For SCSI devices it searches from highest ID to lowest for a partition with a bootable system. Not sure about IDE drives.
    * cmd-opt-shift-delete-# -- Boot from a specific SCSI ID # (# = SCSI ID number)
    * cmd-opt-p-r -- Zap PRAM. Hold down until second chime.
    * cmd-opt-n-v -- Clear NV RAM. Similar to reset-all in Open Firmware.
    * cmd-opt-o-f -- Boot into open firmware
    * cmd-opt-t-v -- Force Quadra AV machines to use TV as a monitor
    * cmd-opt-x-o -- Boot from ROM (Mac Classic only)
    * cmd-opt-a-v -- Force an AV monitor to be recognized as one
    * c -- Boot from CD. If set to boot to X and no CD is present, may boot to 9.
    * d -- Force the internal hard disk to be the startup device
    * n -- Hold down until Mac logo, will attempt to boot from network server (using BOOTP or TFTP)
    * r -- Force PowerBooks to reset the screen
    * t -- Put FireWire machine into FireWire Target Disk mode
    * z -- Attempt to boot using the devalias zip from first bootable partition found
    * shift -- (Classic only) Disable Extensions
    * shift -- (OS X, 10.1.3 and later) Disables login items. Also disables non-essential kernel extensions (safe boot mode)
    * cmd -- (Classic only) Boot with Virtual Memory off
    * space -- (Classic only) Trigger extension manager at boot-up
    * cmd-v -- (OS X only) show console messages during boot
    * cmd-s -- (OS X only) boot into single user mode
Did not work simply 'z'?
You could buy an external DVD drive. It needs to be firewire and bootable by Mac OS. If you have another PPC with firewire, you could try target Disk mode and installed tiger that way.
You need to figure out the level of your  firmware before installing 10.2 or greater. ( The PC name for firmware is BIOS. ) Installing 10.2 with a down level firmware will most likely make your iMac unusable and difficult to fix.
What is Open Firmware?
The firmware on a PPC is called Open Firmware. Open Firmware software receives control when you poweron your machine.  It does some hardware testing and some hardware configuration then passes control to your version of Mac OS.   It reside on a PROM ( program read only memory ) chip on the logic board.
Figuring out what level of Open Firmware you have?
1) Mac OS 9.x or 8.x, you need to use the Apple System Profiler.
Apple -> Apple System Profiler
2) Mac OS X, use the System Profiler.
Apple -> About This Mac
click on the More Info... tab
click on Hardware
read the Boot ROM Version
3) Open Firmware, boot into Open Firmware.
Power on your iMac while holding down command+option+o+f
The first output line contains the firmware level. Mine reads:
Apple PowerMac4,1 4.1.9f1 BootRom built on 09/14/01 at 13.18.04
Copyright 1994-2001 Apple Computer Inc.
On my machine, I have 4.1.9f1.
What firmware do you need?
http://support.apple.com/kb/HT1395
You can download the firmware from this page:
http://support.apple.com/kb/DL1283
filename: N-iMac_FWUpdate_4.1.9.smi.bin
                avoid   expanding the file on the download computer.
For a slot loading iMac, this article indicates that you need to be running 9.1 or later version of Mac OS Classic.
http://support.apple.com/kb/DL1283
"The iMac Firmware Update 4.1.9 will only run on iMac computers with slot-loading CD or DVD drives running Mac OS 9.1 or later from a local drive. If you are using Mac OS X you must boot from a local Mac OS 9.1 or later writeable partition (not a CD, or network disk) prior to following the update instructions."
You can download the Mac OS 9 updates from the Apple site.
http://support.apple.com/kb/HT1387?viewlocale=en_US
For tiger, you need 256meg of memory.  A slot loader will take 1gig of memory.
You may need to get more memory.
get the 512meg card(s)
http://eshop.macsales.com/shop/apple/memory/iMac/G3_450MHz_500MHz_600MHz_700MHz
Mac OS X 10.4: System requirements
http://support.apple.com/kb/HT1514
PPC 10.4.11 combo update.
http://support.apple.com/kb/dl170