I get this message:

FATAL ERROR:
SYSTEM.IO.FILENOTFOUNDEXCEPTION:COULD NOT LOAD FILE OR ASSEMBLY 'MICROSOFT.xNA. Framweork, Version 4.0.0.0.0, Culture=neutral, PublickeyToken-845cf8be1de50550' or one of its dependencies. The system cannon find the file specified.
Application will now exit.

HELP PLEASE

David Pope