bios is not able to detect the hard drive ....
possible the drive has died ,or the boot sector has been corrupted .
things to check :first check cable connections ,then enter the bios and see if the hard drive is showing correctly .
if the drive shows in the bios then the boot sector is corrupted ,if not then the drive is dead .
if its the boot sector ,this can be repaired .
let us know when you find out for more advice.