Ensure you have anti-virus and anti-spam software installed on your network. The software should also be updated regularly (most do this automatically but do check).
Windows Defender comes pre-installed on all versions of Windows 8 and later operating systems. It runs in the background and tell you when you need to take specific action.
There are also several free software downloads available so there is no excuse not to have anti-virus and anti-spam software installed on your computer.