"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 Win7 Ultimate to Win7 Prof.

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 problem.

...Help....

 

Guys, what can you recommend? how to be?

 

Follow to the next steps:

Save the file in the Microsoft Project Database format:

1. Open your problem file (it may help to turn off automatic calculation if the file is reluctant to open).

2. Select File/Save As...

3. Save as type: Project Database (*.mpd) then click Save.

4. Close the file.

5. Re-open it from the .mpd file.

6. Select File/Save As... and save it as an .mpp file again.

 

If these Troubleshooting steps don't help, then You'll probably going to have to start looking at data ms project recovery tool, as Project Recovery Toolbox because it sounds like the header is corrupt. http://www.oemailrecovery.com/project_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 ms project recovery.

 

Try some of these troubleshooting steps:

FAQs

 

You've been very kind in your efforts to help. Thanks for that.

 

The first thing to do is to get to know the format of your file. With that in mind I'd suggest you this intuitive tool File Type Advisor . This effective soft will definitely help you regognize the file format and recommend you a program to open it.