If the file was overwritten, you will never be able to recover it. Not even the Department of Defense can recover the original file once overwritten. (Which is, incidentally, the reason there's a DoD standard for security-wiping hard-drives that involves multiple overwrites to remove data)
If the file was simply deleted, and no new data was written to the same clusters on the hard-drive, then it is easily recoverable. There are a lot of paid programs or services you can use to do this reliably, assuming the space where the original data resided on the hard-drive was not overwritten with new data (which is very likely, considering that when you "delete" something, it is not actually erased, but simply tagged as "overwritable" in a sense, whereupon new data is free to be stored in that area, if you're unlucky)
So, if you're sure the data has been overwritten, it's lost.
If you think it may have only been deleted, then you have a chance.
9 times out of 10, a corrupted file means a portion of it has been overwritten for whatever reason, so that portion can never be recovered, thus rendering the file as a whole, irrecoverable. Short answer.
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