I didn't do anything to it except let Windows screw up its ability to be mounted/unmounted, somehow. I KNOW this external hdd should be recoverable. I'm still on that Puppy Linux LiveCD right now as I type. My Ubuntu laptop, however, is no longer usable - after I copied the 130GB of files I wanted to save to my external hdd, I attempted an upgrade of Ubuntu.

So since it won't 'unmount safely', I just unplug it (probably a mistake, but I didn't see that I had any other choice at the moment), then try mounting it using a LiveCD of Puppy Linux - Puppy will not mount it, just gives an error but no details. I was accessing files from the drive from within Windows just fine minutes before. I also get another error: drive is corrupt, run chkdsk utility. Then suddenly a message pops up - cannot write to drive. Tried it several more times, waiting a minute or two between each try - same thing. It told me that it could not remove the external drive because another program was accessing it. Then I tried to do the 'Safely Remove Hardware' thing. Just to test it, I plugged it into an older Windows XP machine, and it seemed to work just fine. It has about 130GB of data I spent 3 hours copying to it yesterday from my Ubuntu laptop. I had a perfectly working Western Digital 250GB external usb hdd about 30 minutes ago.

Testdisk repair mft