Moving files from back up to new internal drive

[rfrankel]

I just backed up my internal iMac G5 drive to a new external Seagate 400gb firewire/usb2 drive with an (unregistered) copy of Super Duper.

The back up seemed to go OK, but when I tried to boot from it I discovered that it was not a bootable drive. I erased it and tried to install a new copy of OS X but got the error message that the system could not be installed on the Seagate drive. Can't figure that out because I can boot from an older Seagate 400 just fine.

I will now back up my iMac drive again. My question is about the best way to move those backed up files to my iMac when the iMac drive is replaced tomorrow.

Do I just reverse the back up process, backing up the external Seagate to the newly replaced drive on the iMac? (My concern here is that the lack of bootability of the Seagate was not a disc/hardware issue but had something to do with bad files. The Seagate was formated Mac OS extended and I ran the Disc Utility fix and repair options.)

Or can I just drag and drop all the files from the external Seagate onto the new drive in the iMac? (I've heard that if there's more than one user on your drive (3 on mine) that could be a problem)

And if the Seagate backup has an up-to-date system on it (it does, even though it won't boot) does that mean I should not install a system on the new iMac drive before transferring the files to it?

Finally, would I be able to use OS X's Migration Assistant to back up to the iMac? That is, would the external Seagate drive be recognized as a different "computer" in this context. Of course that means I would install a new system on the new iMac drive.