Can you still read your latest backup? That's a far safer and probably faster way than repair a corrupted file. Being a professional project manager (you are, aren't you) you certainly backup your stuff.
Google finds the usual repair programs. Since they are spammed here often, we'll delete any answer pointing to such a program and let you search yourself. A good search term to start with is REPAIR MS PROJECT.
To eiiminate the rist of spam, I'll lock the thread.
Hi there, I have a project file that doesn't open. When you try to open it it gives the following error: The file "<filename>" cannot be opened. Check that the file name and path are correct. Check that the file format is recognized by microsoft project blah blah blah.