One trick I have learned as a technician, when the problem is data-read errors off the platters themselves, is to freeze the hard drive overnight. It makes the data more 'readable,' but for a one-shot deal. If this data is critical, and you have a replacement hard drive (which, if it's a drive failure, you probably do), then you can hook up your frozen hard drive and immediately fetch the data off before it warms up
Here are some drive recovery tricks that have worked for me, in the order that I do them. Try booting the drive and copying the data off after every step.
1. Hold the drive upside down, making gravity change the head geometry ever so slightly. Vertical is also another option.
2. Slightly rap the drive with your knuckle, (but nowhere near hard enough to damage the drive).
3. Try the drive in another machine, (slight drive voltage change assumed to be the miracle worker here).
4. Rap the drive just SLIGHTLY harder than you did above in 2.
5. Freeze the hard drive in the freezer for two hours, and place in a plastic zip lock bag to prevent condensation from forming on the drive when you plug it back into the system, (head geometry, electrical resistance lowered, electrical contact points adjusted, etc., assumed to be the miracle here).
6. After the drive warms up to room temperature or better, rap it even harder with your knuckle this time.
7. Repeat all of above steps on next day, as sometimes I've gotten data off drive simply by trying again.
