Erm...see if you can search back to my HD fail thread. It's exactly what happened to me. Thumbnails were there, but in many cases, no pics. Half way through a folder, one or two perfect pictures would be there.
One of the utils I tried was a $49 program that offered a freebie go - it only allowed one at time. Very looooong procedure. It worked! So, the implication was, that if you paid, it would have been a solution. The cheepies - the few that I tried - simply did not work.
In my case, there were so many backups, my only problem was where the @#$^%@ were they? Even to what country were they in...etc.. It was easier to seek the backups than to restore the lost ones.
I lost my HD after installing W7 on a newer drive and using the old drive as a second unit. It was NOT configured as a slave, but was switched via the BIOS to be the boot drive or not. It was when I allowed CHKDSK to run into the old drive that the damage was done. Coincidence? Maybe...but another poster had the same thing happen shortly afterwords.