Ransomware and malicious downloads are two of the most common ways home computer users get into serious trouble. The good news? A few straightforward habits can dramatically reduce your risk – and if the worst happens, knowing exactly what to do next makes all the difference.

Understanding the Threat

Ransomware is a type of malicious software that locks your files – or sometimes your entire computer – and demands payment to unlock them. It often arrives through a malicious download or an infected email attachment. Once it runs, it can spread quickly through your documents, photos, and personal records. Malicious downloads are equally sneaky: they might be disguised as a software update, an invoice, or a video player you need to watch a clip. The moment you open them, they can install malware, steal passwords, or hand control of your machine to a criminal. The key is to stop these threats before they take hold.

Back Up Your Important Files – Early and Often

A reliable backup is your best insurance against ransomware. If your files are locked, you can wipe the computer and restore everything from a clean copy. Follow the 3-2-1 rule: keep three copies of your data, on two different types of media, with one copy stored off-site. For example, you might keep your main files on your computer, a second copy on an external hard drive, and a third copy in a secure cloud service that keeps version history. Set your backup software to run automatically – daily if possible – and test that you can actually restore a file. A backup you never check is not a backup. Remember to disconnect the external drive after backing up, so ransomware cannot encrypt it too.

Be Wary of Unexpected Attachments and Downloads

Most ransomware infections start with a simple click. Treat every unexpected email attachment as suspicious, even if it appears to come from a friend or colleague. If you weren't expecting a document, call or message the sender using a different method to confirm it's genuine. Be especially cautious with file types like .exe, .scr, .js, .zip, and .docm – these are common carriers for malware. When downloading software, stick to the developer's own website or a trusted app store. Avoid pop-up adverts that claim your computer is infected or needs an urgent update; those are almost always scams. Hover over links to see where they really lead, and never enable macros in a document unless you fully trust the source and know why they are needed.

Keep Your Software Updated (and Don't Ignore Those Prompts)

Software updates are not just about new features – they patch security holes that criminals actively exploit. Turn on automatic updates for your operating system, your web browser, and any security software you use. When your computer asks to restart, do it as soon as it's convenient; putting it off for weeks leaves you vulnerable. The same goes for other programs you use regularly, such as PDF readers, media players, and office suites. If a program no longer receives updates, consider replacing it with a supported alternative. And if you see a prompt to update a program you don't recognise, close it and check directly through the program's own menu – fake update pop-ups are a favourite trick of malware distributors.

If Your Files Get Locked: Immediate Steps to Take

If you discover a ransom note or find your files suddenly encrypted, act calmly and quickly. Here is what to do straight away:

• Disconnect from the network. Unplug the Ethernet cable, turn off Wi-Fi, and disable any other connections. This stops the ransomware from communicating with its controller and may prevent it from spreading to other devices on your home network.
• Do not pay the ransom. It funds criminal activity and does not guarantee you will get your files back.
• Take a photo of the ransom note with your phone, then shut down the computer.
• Seek trusted advice from a reputable computer repair specialist or a knowledgeable friend.

If you have a recent backup, you can wipe the computer and restore your files – but only after the malware has been completely removed. Change any important passwords from a different, clean device. Finally, report the incident to the relevant national fraud or cybercrime reporting service – it helps others and may assist with recovery.