Sorry to hear it! Zip up the entire folder that contains the .chproj file, and send it to me via direct message (using a service like wetransfer.com / dropbox / etc), and we'll take a look to see if we can recover it.
BTW, Ch version 4.0 and later (current is 4.4) have a new project format that is much less like to become corrupted. I highly recommend updating.