Recovering NEF images

Hi,
After my HD went into a coma, I tried recovering the hundreds of images that were under the Nikon Photo format NEF. I got about half of them back. The other half were partially recovered (half the image is fine and half of it with just pure fuzz and noise) which isn't enough for Nikon Software to open them. Can anyone recommend a recovery program that can REALLY do the job? I've tried it twice with 2 different products and I'd like to think that I'll be lucky the third time. One of them was one of the highest rating for recovery on some site. It was free though, so I can't really complain.
Any suggestions or recmmendations.
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