You will to need to restore the Master Boot Record for Windows 7 Again.
How to run the Bootrec.exe tool
1)Put the Windows Windows 7 media in the DVD drive, and then start the computer.
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)Select the operating system that you want to repair, and then click Next.
6)In the System Recovery Options dialog box, click Command Prompt.
7)Type Bootrec.exe, and then press Enter.
If that doesnt do anything try with
Bootrec.exe /FixMbr
This option writes a Windows 7 MBR to the system partition. It does not overwrite the existing partition table. Use this option when you must resolve MBR corruption issues, or when you have to remove nonstandard code from the MBR