My old partition is gone! Mac will no longer boot!

[Stilgar1973]

This is an old Emac running 10.4.whateverlatestis

We purchased a new imac today, we expect it to arrive by next Monday. I have been tasked with getting the old information off the emac in a way that would allow us to restore it to the new imac.

I am a windows man (oh no the devil! ) but I am trying my bestest to learn my way around my Father-in-law's mac fetish.

I found some reviews that said that SuperDuper! was the only backup software worth considering for the mac. I like the try before you buy.

I installed it on his emac.
I found I could not write to the DVD RW drive.
I decided to do an initial backup directly to the desktop. I would do the backup and then figure out how to get the information from his mac to some sort of storage medium.

I started the software and it ran - forever. It said that it was going to copy 1.6 gigs of data, but it was taking forever and a day. I assumed it was compressing. I decided that was fine.

His machine has some issues with lockups when it tries to sleep, I disabled sleep and went to bed.

I got up this morning and it had rebooted.
The old disk partion called MAC OSX is no where to be seen.
The computer had rebooted but was unable to start because it couldn't find any active partition.
I put in the 10.4 disc, held in the c key and began poking around.
What I found is that the old partition is gone, just *poof* and there is a new partition in its place called OS2
That new partition has nothing in it. I tried repairing it, but I got an error.

I really need that old partition back.
I have no idea where to go from here.