In case you’re not already familiar with it, “ransomware” is software that installs itself on your computer, scrambles your files so you can’t use them anymore, and then holds them ransom until you send money to the ransomer. (Via bitcoin, so (s)he cannot be identified.) Depending on who “sent” the software, sending the money may not get control of your computer back for you; some of the attackers are just scammers and don’t bother.