Well, the Good News is I don't think the Hard Drive is Bad !!!
Starting from Your Power Supply, Take a DC Volts Reading, & Report back.
Take the + Lead & Trace out where it goes & take a reading after each device it passes thur.
(You are looking for a Voltage Drop (not @ a Regulator !))
Sorry, I Can't really Help, as I Don't have a Webplayer,
But this will be a Great Start for anyone who might be able to Help &
You could just get Lucky & find the Problem Yourself ! Good Luck !