Security

For which operating system?

For GNU/Linux systems you usually don't need an antivirus program.

For Windows, most of the time Windows Defender is enough.

If you're worried about cryptolockers (which you should be), you may want to enable conditional folder access in Windows Defender, a Mandatory Access Control (MAC) system like AppArmor, Firejail or SELinux in GNU/Linux.

You also really want to do backups. If you don't have automated backups, create a manual backup now and start automating your backups. Software like Duplicati or Vorta can help you with that.

It depends on your usage. For basic things on Linux you should use ClamAV, the same on Windows 10/11 with Microsoft Defender. Otherwise you should invest in solutions like BitDefender (or Kaspersky if you really care) or GDATA.

Linux