Your problem is easily solved. Simply restore your C drive from backups!
Just kidding. Despite the fact that the data on your C drive is crucial, I know that you will never back it up. Not even before you run a repartioning tool to install a BETA release of an OS.
Well, you might try
File Scavenger. And while you're on that page, click on QueTek's data recovery link. If the C drive is worth the $500 to $1000 that they will charge you, do that before you try the Scavenger yourself.