Try checking your hard drive connection power and IDA or SATA.
Shut down your computer, Take the cover off now find your hard drive and check to see if the power,IDE,or SATA connection are good and snug.
If the problem still exists then repair MBR
Repairing the Master Boot Record
If you want to restore the master boot record, you can simply type in the following command in CMD:
You can also write a new boot sector onto the system partition with this command (which is often more useful):
And of course, if you just use bootrec /? you’ll be able to see all the options.