Hold it in your hand (very carefully!!!) when the computer is booting to try to tell if the actual HEAD inside is broken or just the circuit board on the outside is what is bad. Then inspect the board VERY CAREFULLY to see if there are any burn marks or signs of damage. If you KNOW the hard drive is bad, you could try to buy another of the same model and swap the circuit boards with the working one (That has worked for me before...)

Other than that, if you find out that the drive is fine, its just the MBR or data itself, there are many tools you can use to access the data...