You can nuke an infected computer and start from scratch without losing anything, but only if your backups aren't also held to ransom.

If you're not backing up your irreplaceable files like family photos and business records then you're setting yourself up for disaster. Ransomware attacks like WannaCry aren't the only threat to your data, you're also at the mercy of fire, flood, theft, hardware failure and simple human error.

Don't make the mistake of thinking that these kinds of disasters only befall other people, there are already plenty of young people who will have no baby photos to show at their 21st birthday after their parents lost everything in a tech disaster.

Ransomware attacks are also becoming a lot more cunning: rather than far fetched claims that you've won the lottery or inherited millions, they dress themselves up as innocent-looking utilities bills which even the most vigilant of us could click on without thinking twice.

If you can't afford to lose every important file on your computer, smartphone and tablet then you can afford to spend a little time setting up a solid backup regime. With backups of your most precious files tucked away for safekeeping you can ignore ransomware demands, wipe your device and start from scratch.

The best backup systems run automatically in the background, although this convenience can actually work against you in the case of ransomware which encrypts all the important files on your computer. You're in big trouble if you've automatically backed up those locked files and written over the originals.

Backup your backups

This is why you need a backup system which keeps previous versions of your files, so if you've backed up an infected file you can go back in time and recover an earlier version of the file. Unfortunately these kinds of recovery features vary widely between various backup and storage services, so you need to do your research before committing yourself.

As a general rule, dedicated backup software and services tend to offer more advanced features and granular control than cloud storage/sync services. Business-grade services also tend to offer better protection than consumer-grade services. Some services will only keep previous versions of Office documents and not other file types such as images. Others might keep previous versions of all files, but only for a short amount of time such as 30 days.

Some backup systems also offer the convenience of "mapping" your backup drive to your computer, so it appears as an attached hard drive even though it's actually stored on a network drive or in the cloud. These days mapping your backup drive is a bad idea, because if your computer is infected by ransomware it can spread to mapped drives and take out your backups.

Whichever backup service you settle on, it's important to test it regularly. Don't just check that the backups are running, also occasionally try recovering a few files to ensure that the backups are intact. If you need special software with a registration key to recovery your files, make sure you've made arrangements for this.

A little bit of paranoia goes a long way when it comes to keeping your data safe. What's your backup strategy? Has it saved the day when disaster struck?