Remove it from the computer, using the 'Add-Remove Programs' control panel in Windows, then re-install it. When you reinstall it, be sure to choose the language called 'English', not the language called 'French'.
Although I don't think that removing the program erases your map unlock codes, it would probably be a good idea to back up (export) your map unlock codes before removing the program. You can save the export file to the desktop, and easily re-import it later if needed. This will save you having to type in all the numbers again.
Michael
