[Photo Guy]

Hello!
I used SuperDuper! to make a copy of an internal hd for backup purposes and everything seemed to go fine. SD quit after it finished. I opened Pages to work on a project and after saving it, Pages crashed. I clicked the Ignore button and then the whole OS froze up. My only choice was to do a hard restart via the power button on front.

After that the internal drive that has a lot of data on it (ironically that I was trying to back up) didn't show up on the desktop. I ran Disk Utility and the drive was there but the icon was the plain white 'page'. Clicking Repair Drive gave back 'ERROR: Drive cannot be unmounted'.
I tried a simple restart in hopes it would magically reappear. No luck. Now the drive doesn't even show up in Disk Utility and still not on the desktop.

I have read many posts but still couldn't find an answer how to get the drive back. Any help will be so much appreciated!
Is there a Unix command I can use to tell what file is still open and won't let it unmount?
And if so, how do I close that file so it will mount again?
I haven't tried any but read that many tried DiskWarrior, TechTool & others with no success.

Any ideas are welcome and appreciated!!! Have I left any necessary/important info out of this post?