Project 2003 says "Project cannot open the file"

I have a user that has been using Project 2003 for several years.  He last used one particular file in November, and now when he tries to open it he gets this error message:
Project cannot open the file
--check that the file name & Path are correct
--check that the file format is recognized by project
It is a .mpp file, and was created with and had all modifications done with project 2003.  The only thing that has changed in the last several months is an upgrade from Win 2000 to Win XP pro.

I have tried opening this file on other computers and I get the same error message.  
I have done a new/fresh install on a computer - same problem
I have repaired and also removed/reinstalled - same prblem

...Help....

I need you to look this subject on this authoritative source. Maybe find something useful?

https://social.techn...rver2010general

Try some of these troubleshooting steps:

http://project.mvps....on_and/or_bloat

If these Troubleshooting steps don't help, then You'll probably going to have to start looking at data recovery tools, as is sounds like the header is corrupt.  http://www.oemailrec...t_recovery.html

I have tried it and you too could see as this tool works. Make sure you have a back up of the current file before attempting any kind of repair.

thanks for great advice..