Fix the MBR in Windows 8 You need the a copy of Windows 8 installation DVD before you repair the Master boot record.
(Don’t have a Windows disc? there is other ways of repair MBR, like Hirens Boot CD)
Boot from the windows installation DVD or USB
Click Repair your computer
First lets try Startup Repair
Select Operating System you wish to repair
It will now diagnose you operating system and try and repair it.
Reboot computer to see if issue is fix? still getting error or issue on boot up? carry on to next step.
Reboot back to this option and select Command Prompt
Navigate to your windows directory like I have done in the image below, make sure you have the right drive letter, you can check by typing dir once in right directory type the commands one at a time.
bootrec /FixMbr bootrec /FixBoot bootrec /ScanOs bootrec /RebuildBcd Press enter after each command, that's it all done. Remove DVD or USB and then type exit. Now restart your computer and see if its fixed