Asus G50V hardware problem

My G50V - about 4 years old, Windows 7, 2 HDs - suddenly crashed and when I tried to reboot it, I kept getting the message 'missing operating system.' Was finally able to enter BIOS and reset the BIOS defaults (based on a recommendation I found online). The computer then booted normally, only when I go to 'My Computer' the two drives on my second HD (F and G) are no longer listed. My backups are on G. Am I to conclude the HD is fried? Is there a way to recover the contents? Thanks.