It's called ransomware. Options you have are:
1 - Take it to some good computer shop where they might fix, which I doubt.
3- Hope you don't have any important files because it will really delete all your stuff
Edit: After a quick google search I saw that it is possible to remove ransomware but CryptoLocker is one of the hardest. You should look up on google how to remove CryptoLocker ransomware