Malware is the term used to describe computer code that’s been designed to get up to no good. Viruses, spyware, ransomware and worms are all different types of malware.

Regardless of the type, malware is something to keep well away from your PC – but platitudes won’t help if your computer is already infected.

While there are dozens of different types of malware – and many more methods still to remove specific infections – over the next few steps we’ll explain what to do if you suspect your Windows PC to be marred by malware.

You proceed at your own risk so, if possible, back up your personal files and folders before beginning.


Step 1: Update existing security software and scan

Good security software will spot and stop known malware infections in their tracks. However, new malware surfaces every day, so it is important to update your scanning tool.

BT Customers can download BT Virus Protect, which is powered by McAfee security. It’s free for all BT broadband customers. 

If you haven’t updated for a while, do so now - and then use the program to scan your entire computer.

Expect the process to take a long while – perhaps several hours. If an infection is indentified, follow your security software’s prompts.

If you don’t have security software installed, we’d suggest you download and install protection as soon as possible.

If your PC won’t even launch Windows and you suspect a malware infection, skip to Step 5.

Step 2: Download specialist removal software

Microsoft Download Centre

As noted in the introduction, malware takes many shapes – so there’s no one-size-fits-all solution for removing these electronic interlopers.

However, the commonest malware infections can be eradicated using dedicated removal tools. Microsoft, for example, offers its Malicious Software Removal Tool free of charge. It works on Windows 10, Windows 8.1, Windows 7 and Windows Vista.

Download the file and then read the next step to learn how to use it. If you’ve previously downloaded and used Malicious Software Removal Tool, do so afresh – because Microsoft regularly updates it to include the latest malware information.

Step 3: Scan with Malicious Software Removal Tool

Protect your computer against threats 3

Microsoft’s Malicious Software Removal Tool doesn’t require installation – just double-click the downloaded file to launch the program.

If Windows displays a Security Warning message make sure you’re launching the correct file and then click Run – Malicious Software Removal Tool is safe to use.

Click Next and you’ll be offered a choice of scan type. Unless you’re in a hurry, we’d strongly advise selecting the ‘Full scan’ radio button before clicking Next.

Step 4: Wait, and then read the report

Protect your computer against threats 4 A

Malicious Software Removal Tool will now scan everything on your PC – expect it to take several hours to do so. A progress bar will be displayed.

Protect your computer against threats 4 B

When the scan has finished a report will be displayed. Follow the prompts or, for more information, click the ‘View detailed results of the scan’ link.

Step 5: Start in Safe Mode

Protect your computer against threats 5

If your PC won’t even load Windows then you’ll need to take a step back to try launching in Safe Mode: this is a special stripped-down version of Windows that provides access to basic tools.
For Windows 7 you’ll need to do the following: First, find the F8 key on the keyboard – and hover your finger above it in readiness. Now switch on the PC and tap F8 repeatedly as the computer goes about its start-up business.
If you get the timing right, this Windows Advanced Options Menu screen will appear. Use the cursor (arrow) keys to move the highlighter to ‘Safe Mode with Networking’. Press Enter.
If you’re on Windows 10, getting to the Safe Mode is a little different. From the Start Menu, hold down the Shift button and click Restart.
Using the arrow keys on your keyboard, go to TroubleshootAdvanced optionsStartup Settings and Restart.
Then click the 5 key on your keyboard.
When Windows starts, it will look a little odd – but don’t be alarmed, as this is normal. Click Yes to proceed using Windows in Safe Mode. Now follow Steps 2, 3 and 4 to download, install and run Microsoft’s Malicious Software Removal Tool.

Step 6: Launch your PC with a rescue disc

Protect your computer against threats 6

If all else has failed then you may need to resort to a ‘rescue disc’ to recover your PC.

Some manufacturers include rescue discs with their computers but understand that these typically restore a PC back to its ‘factory’ state – so you might end up losing all your personal files and folders.

As an alternative, get a friend with a working PC to download the free Kaspersky Rescue Disk and use disc-burning software to create a ‘bootable’ CD or DVD disc.

Pop this disc in your own PC’s drive, switch on and then follow the prompts to start your computer from the Kaspersky Rescue Disk – and allow it to scan and attempt to remove any found malware.

Did you manage to sort out your PC? Let us know in the Comments section below.

Updated by Jamie Harris on 06/10/2016.