Leopard install is stuck halfway through. How do I get out?

Question

I have a Power Mac G4, currently running OSX 10.3.9. Today I bought the installer disc for Leopard, and began an install.
The install is stuck on the "Installing" screen (which comes after it checks your disc is OK). I have the dreaded spinning beachball of death, and the thin blue line in the progress bar is going nowhere. Under the progress bar it says "Time remaining: Calculating...
My G4 specs:
Power PC G4 (3.3)
OSX 10.3.9
Processor: 1.25GHz
Memory: 1.25GB DDR SDRAM
I set the disc going in the lower DVD chamber (not the DVD player that came with the Mac, but another one I had installed that also has a DVD burner). Is it possible that my Mac doesn't like me using this DVD drive?
Help! How do I stop it and try again? I don't want to just shut down my machine in case I kill in mid-install. Is there a way of force-quitting the install or something?

Answer 1

A halfway installed operating system is not totally lost necessarily. It could just be a bad directory, or insufficient space, or a corrupt file somewhere that has yielded an issue installing. Regardless, you can attempt to recover data to an empty Firewire external hard drive at least the same size as your internal drive using Prosoft Data Rescue, Subrosasoft Filesalvage, or Boomerang's Boomerang if you can't mount the hard drive via Target Disk Mode using another Mac or booting that external hard drive from a second partition. To mount it via Target Disk Mode do this set of instructions:
http://www.info.apple.com/kbnum/n58583
Your recovered files won't be bootable, and registration codes won't be saved, but at least your data has a good chance of being saved if you do one of the above.
If you decide to get a second Firewire hard drive, my recommendation is to get one at least 20 GB larger than your internal hard drive, partition it, and install Leopard, Superduper, and one or all of the data recovery programs (Data Rescue, Filesalvage, Boomerang) on the 20 GB partition, and leaving the empty partition to recover data to. If you can boot that external hard drive's partition and do that recovery in one way or another, then you can safely analyze why the internal hard drive failed installation.
To boot the external hard drive after installing the operating system on it, use the Startup Manager below:
http://www.info.apple.com/kbnum/n106178
If none of the three recovery utilities can see the internal hard drive, then a data recovery specialist such as http://www.drivesavers.com/ is necessary. They are expensive.
This is why you should always backup before installing new software, and after saving any important data. See my backup FAQ*:
http://www.macmaps.com/backup.html
- * Links to my pages may give me compensation.