Petya Ransomware
Ransom-ware generally presents users with an ultimatum: pay a fee to unlock and reclaim personal data, or don’t pay the fee and lose the data indefinitely. Ransom-ware is able to automatically corrupt and delete files in the event that monetary compensation is not received, leaving most users with little time to resolve the problem through alternate means. but the truth is you don't need to pay the hackers because there is no guarantee that you will be able to regain access to your files.
Be sure you are backing up your data on a regular basis. If you do become a victim of a ransom-ware attack, you will be able to restore any impacted files from a known good backup. Restoration of your files from a backup is the fastest way to regain access to your data. This is the biggest virus affecting a lot of companies.