You might try a boot to repair, but your hard drive is likely gone beyond useful repair.
I would put it in another machine as a slave, or in an external hard drive enclosure to see if you can read the data. If so, it would be very smart to save your email, documents and settings, accounting files, music, pictures, and anything else that is important to you before you try any recovery options.
Very often the damage is only to the first 8 sectors of the hard drive, and the data is still available for backup or rescue.
But sometimes, when you have a power-type failure with a failed power supply, or a temporary failure of you main electricity to the building, the drive can be electrocuted...
Since it is only one drive, it is likely just a normal hard drive failure... particularly if it is a Maxtor or Hitachi or Samsung which seem to do this all the time nowadays. But even in full failures, if the drive can be encouraged to spin, you can save data.
If your data is important, and you have never saved data before, it would be wise to find a person who knows how and can assist you.
