In a word…
Ransomware is making the rounds. I have seen this malware in action recently. The only way to guard against it is to do your backups regularly. An image backup is best because it restores all of your programs as well as data but… if your machine is infected with ransomware, you may have other infections as well. It is safest to format and rebuild from scratch. Then bring back your data, programs and preferences. Paying the ransom is not advised. You may or may not get the correct unlocking key. But you will be charged for it, right or wrong.
Check to see if the website that you are accessing is safe against the Heartbeat vulnerability. Click here to go to SSLLABS.