error loading kernel in SUM

You are trying to boot from the drive? It would appear that the OS is hosed, thus preventing boot.

You should boot to a seperate drive and pull the user files off in a drag and drop fashion if at all possible.

Data Rescue 3 would definitely be able to pull the files, though the resource forks will be gone, with the need to sort remaining.

Is the drive getting too hot?

Can you copy smaller portions off it?

If you have DiskWarrior try holding the Option/alt key while selecting Rebuild, the Scavenge, which can build an alternate directory that can allow backing up from that directory... it's worked a couple of times when nothing else did. Can takes days trying sometimes though.

I'd for sure work on the cooling, can you run it with the USB case open? And a Fan?

That should help, good luck. 🙂

I doubt it, but try this...

1. Insert the Mac OS X Install disc that came with your computer, then restart the computer while holding the C key.

2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)

*Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.*

3. Click the Erase tab.

4. Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.

5. Select your Mac OS X volume.

6. Highlight the drive, select Partition Tab, then Format type... MacOS Extended Journalled, select the Security Options button, choose Zero Out Data, Erase... after completion hopefully you'll be able to install.

You can "Archive and Install: Preserving User Settings", with the "Preserve User Settings" being very important.

This retains all your data and such in a "Previous System" folder and installs a new OS X.

http://support.apple.com/kb/HT1545

http://support.apple.com/kb/ht1710

As to whether or not the drive will take the "abuse", that remains to be seen.

Do you think "Archive and Install: Preserving User Settings" would make the drive stable enough to copy off the user folder?

It is probable that it will if the issue is indeed just missing OS X files.

It can also help in the case of corrupt files.

It is very hard to say, though, not knowing any more about the issue than what is said here...

Call it a YMMV type of deal (Your Mileage May Vary).

I do not want to risk losing the user folder contents. I can see that everything appears to be there, but I only get 3-4 minutes before the bad drive disconnects.

Any writing on or heavy use of a compromised disk is risky.

If the drive "goes away" during the A&I, things will likely get worse as far as file availability.

I would backup/copy whatever I could, even if it is one file/one document/one photo at a time, before the A&I.

Otherwise..... well, the "otherwise" makes me nervous.........