These were commands used for vista, but should still hold true for Windows 7. I've just never needed to use them yet......knock on wood
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.