Change Windows 7 Pro display language

Download the MUI (Multilingual User Interface) for your language: http://www.froggie.sk/7lp64sp1.html

After the download completes, open a command line prompt as administrator and type
DISM /Online /Add-Package /PackagePath:C:\lp.cab
bcdedit /set {current} locale fr-FR [For French]
bcdboot %WinDir% /l fr-FR

Open regedit.exe and delete the en-EN key under
HKEY_LOCAL_MACHINE / SYSTEM / CurrentControlSet / Control / MUI / UILanguages

Reboot.

BOOTMGR IS MISSING

Use the System Recovery cd to boot into the Windows recovery environment. Open a command prompt:

Diskpart -> List disk -> select disk # -> List partition -> Select partition # (# being the OEM or system reserved, not Windows, partition) -> Active -> Exit

Then do all options for Bootrec (/fixmbr, /rebuildbcd, etc) and reboot.