after selecting repair>cmd prompt, enter:
BootRec.exe /fixmbr
you can also substitue the /fixmbr with thes commands:
/FixBoot. Writes a boot sector onto the system partition to start Windows
/ScanOs. Scans all disks for Windows installations and displays them to you.
/RebuildBcd. Scans all disks for Windows installations and prompts you to pick the ones you want to add to the BCD.
BootRec.exe /fixmbr
BootRec.exe /FixBoot
BootRec.exe /ScanOs
BootRec.exe /RebuildBcd