The thing that scares me the most about computers in this day and age is ransomware. Ransomware is malicious software that encrypts your data and then offers to sell you the key to unlock your data. I’ve seen too many people get ransomware on their computers and lose data.
Please always have at least one offline (not connected to your computer) backup of your data. You can buy USB memory sticks very cheaply. Two or three of them can greatly reduce your risks of losing data. That way if you somehow wind up with ransomware on your computer, you can restore from that backup, and turn a disaster into an inconvenience.