Computer viruses are increasingly used by criminal gangs to not only damage your personal data but compromise it - for example by stealing your online banking credentials. They may also use them to take over your computer in order to remotely attack others, or simply use encryption to lock up your data and demand a fee to restore it.
Whatever devices you are using, make sure you have good, up-to-date antivirus software. You need it on all your home computers such as desktops and laptops, and also on some other digital devices you may use such as some smartphones and tablets. If you've already got antivirus, make sure you're not relying on an expired or trial version. And regularly back up your own documents and photos (preferably to an external device which is not normally kept connected), so that if your device ever needs to be completely reset, you haven't lost anything precious.
Recommended free antivirus products
Apple : Sophos Home
Android : Sophos Mobile Security for Android