2. Press a key when you are prompted.
3. Select a language, a time, a currency, a keyboard or an input method, and then click Next.
4. Click Repair your computer.
5. Click the operating system that you want to repair (Windows 7 in this case), and then click Next.
6. In the System Recovery Options dialog box, click Command Prompt.
7. Once in the command prompt, type exactly Bootrec.exe /FixMbr and then press ENTER. You will see "operation completed successfully." (Doesnt even take a second. Dont be alarmed )
8. Reboot and set BIOS to boot from the HDD again.
GRUB will be overwritten in step 7 and Windows boot loader will once again take control of loading your OS(s).
Bootrec.exe /FixMbr
// The /FixMbr option writes a Windows 7 or Windows Vista-compatible MBR to the system partition. This option does not overwrite the existing partition table. Use this option when you must resolve MBR corruption issues, or when you have to remove non-standard code from the MBR.