I don't know if this will work for you but if you have windows 7 try right clicking on your (.capx), and select (properties). When the new window opens select the (Previous Versions) tab. Then you should be able to restore your file from a previous restore point if your computer is set to save restore points. Usually when windows updates, or you install a program like Construct 2 your computer will save a restore point automatically. If it does you will loose all your work back to that point but if your lucky maybe it won't be to much.
You might want to make a copy of all your projects files before trying this though just because someone else might be able to fix it for you.Wink2012-07-14 09:22:57
@thesecretweapon - if you share your project and all its backup files, we can have a go at recovering them.
I'm afraid if nothing can be done, though, you've just learnt the hard way that you should have set up automatic backups! I think I should make Construct 2 prompt you to set that up on startup to help prevent this kind of problem...