Something really suspicious is going on my computer system! Suddenly all my files became inaccessible, and they were renamed, too. By the way, I have found a notepad file, which said that I have to pay 0.5 Bitcoin via Tor browser in order to get my files back. I believe it is a virus, can you please tell me what I have to do to recover my files? They are very important to me and I just cannot lose them now…