Certain things we can try here ,
1)This could be a loose ribbon cable connecting your hard drive to the motherboard , make sure it is connected properly.
2)Your BIOS may not be recognising HD , some settings may need altering but I am not au fait with this so wait for the more technically minded to help you out there.
3)If it is indeed a problem with your O/S then try a repair install click here
Good luck !