I haven't used any kind of antivirus software during all the years I have been using Win XP / 7. I have just used common sence and not opened executable files from unknown or shady sources. It has been working just fine. And no, I haven't been infected without my knowledge since I have been running MBAM and other malware scans maybe once a year and I have never had any stuff on my computer. However yesterday I was browsing Netflix together with Hola (to get US IP for better movie supply). I fell asleep during the movie and when I woke up the next day my computer was still on and a new tab in my browser had opened which basically told me that all my files had been encrypted and I have to pay 500€ to get the private key in order to be able to decrypt the files: https://gyazo.com/1b349a3ad7763c48100918567b799d7f The ONLY reason I can think this happened of is that Hola had some stupid popup or redirection to a website with malicious code that was automatically executed on my computer without my knowledge. I am not crying rivers because of this because I did not have that much important files on my PC, but there are some files that I would like to have back, but I don't want them back enough to pay 500€ for them. All files has a .ccc extension and they are encrypted. Is it possible to recover the files with some file recovery program like Recuva or does that only work for deleted files? I did not have a Windows restore point so what I have done now is that I have saved the encrypted files on a HDD and formatted my C:\ drive and reinstalled Windows.