How To Stop A Computer Virus on Windows With Free Tools

While the thought of a virus infecting your computer can be scary, in many cases, it can be fixed by following a few simple steps and using tools freely available on the Internet. Here's my recommendation for how to stop a virus that has infected your computer.

Download AdwCleaner from Malwarebytes and RKill from BleepingComputer. Ensure the latest Windows Updates are installed and reboot your PC into Safe Mode. Run Rkill followed by AdwCleaner. Restart Windows normally and finish by doing a Full Computer Scan using Windows Defender. 

Let’s go through it step by step. Nine out of ten occasions, this will solve your PC's problems. I’ll also recommend some preventative measures to protect your computer from further infection.

Before we start, a quick explanation of the tools I recommend and why I recommend them.

Recommend Tools


Modern viruses and malware are designed to prevent antivirus applications from detecting them. They do this by hiding in common files, processes and by making changes in Windows’ registry. RKill is a simple tool that stops malware processes from running and restores Windows registry entries that have been altered by malware. To quote RKill's Wiki:

It was created so that we could have an easy to use tool that kills known processes and remove Windows Registry entries that stop a user from using their normal security applications. Simple as that. Nothing fancy. Just kill known malware processes and clean up some Registry keys so that your security programs can do their job.

By itself, RKill isn’t going to clean up your computer. It simply lays the foundations to give antivirus applications the best chance at identifying and removing viruses.


AdwCleaner is a free application from Malwarebytes that detects and removes nasty adware, spyware, and all PUPs (potentially unwanted programs). It does what it says on the tin and does it very well.

Windows Defender

In my opinion Microsoft have put a lot of effort into Windows Defender, their antivirus software. Now packaged up into Windows Security, Defender is the tool we’ll use to identify and remove anything that wasn't caught by AdwCleaner. For many years Windows was plagued by viruses, which led to comparisons with MacOS; incorrectly touted as infallible to viruses. The result was Microsoft built a very solid antivirus solution.

Step By Step Guide

Install the latest Windows Updates.

  • Your best defense against viruses and any security vulnerability are Windows Updates. Windows Updates include the latest virus definitions for Windows Defender. If your PC is infected, it's likely the virus has infected other machines too. In all probability, Microsoft has already identified the malware and released an update to detect and remove it. 
  • You may need to restart your computer several times before Windows Updates are entirely up-to-date. Even if Windows says it is up-to-date, it’s worth restarting and checking again until you’re confident there are no more updates to install.

Download RKill and AdwCleaner.

  • Next step is to download the two programs I recommended. Rather than me linking here to a version of the applications that will become outdated, I’ll link to the websites so you can download the latest versions.
  • Don't run or start the applications just yet, first we'll boot into Windows Safe Mode.

Restart your computer in Safe Mode.

  • By putting Windows into Safe Mode we’re limiting the number of processes and applications starting-up to the bare minimum. You'll notice your display reverts to the minimum resolution and you'll lose your desktop background. Don't be alarmed. Malware and viruses are specifically written to be hidden from antivirus applications. So by limiting the processes and applications that are running, we’re trying to prevent the malware from loading, giving us a better chance of detecting and removing it.
  • Boot into Safe Mode by searching for 'Advanced Starup' and opening the 'Change Advanced Startup Options'.
  • Select Advanced Options > Troubleshoot > Startup Settings. Then click Restart.
  • Upon restarting choose press 4 on your keyboard. Widows will now boot into Safe Mode.

Search for Advanced Startup

Choose Advanced Options

Click on Troubleshoot

Choose Startup Settings.

Click Restart.

After restarting, choose option 4 - Enable Safe Mode.

The computer will start in Safe Mode

Run RKill.

  • Open your Downloads folder, or the folder where you saved Rkill, and double click the application to start it.
  • You'll be prompted to confirm whether you're sure you want to run it. Hit 'Run'.
  • RKill will now do its thing. Be patient. You'll know it's finished because a small text box will appear. Don't close the application just yet.

Run AdwCleaner.

  • Without closing RKill, start the AdwCleaner application by double clicking on the file you downloaded.
  • Click Scan Now to start AdwCleaner.
  • RKill and AdwCleaner will notify you about anything it found, and quarantine any nasty files.
  • AdwCleaner will ask if you wish to run a Basic Repair. There is no need to do this unless AdwCleaner found something on your machine. If so, I recommend running it. 

Restart Windows and open Windows Defender.

  • Having run RKill and AdwCleaner it is now safe to close both applications and restart your PC.
  • After Windows has restarted open Windows Defender by clicking the Shield icon in the system tray, in the bottom-right corner of the screen.

Run a Full System Scan.

  • Having opened Windows Security settings, choose Virus & Threat Protection, followed by 'Scan options'.
  • Choose Full Scan.
  • It is up to you, but I would recommend running RKill again, as you did previously, before starting the Full Scan. There is no harm in running it in normal windows mode and, as before, it will quit any processes that may prevent Windows antivirus from detecting potential infections.
  •  Hit Scan Now to begin. This will take some time, so you can leave it to run.

Windows will now remove anything suspicious it finds on your PC and that concludes the tasks. This process will remove most viruses and malware from your PC. To safeguard against further infections, here's a list of preventative measures I recommend following.

Prevent Viruses By Following These Rules

  • Always keep your operating system, antivirus and software applications current with the latest patches and updates. Software companies never like to admit vulnerabilities in their software. They’re much more likely to say an update is a 'bug fix’. More often than not, however, it’s to patch security weaknesses so always keep your applications updated.
  • Only download applications from reputable sources or known vendors. Never download from third party sites. Be wary, when Googling an application to download, often the top result is not the vendor. It’s worth double checking.
  • Google an application’s name before installing it. A quick browse through Google’s results and YouTube will indicate whether the application is widely used or whether you should be wary of it.
  • Don’t be tempted by third-party websites purporting to offer paid applications for free or on sale. 99% of the time, these websites will be scams. And for the 1% that aren’t, is it worth taking the risk?
  • Never click on unverified links, or download attachments, from distribution emails and an emailer you are not familiar with. Even if you are familiar with the sender, double-check their email address is correct.
  • Finally, periodically run a full system scan of your computer and AdwCleaner. It can be time-consuming but worth doing once a month or so.

Related Content

Pop-up ads are not only annoying; they can be harmful to your computer. Here are three ways to stop pop-up ads in Chrome.Ensure pop-ups are blocked for the site you’re visiting by clicking on the padlock in the address bar and selecting Site Settings. Install AdBlockerPlus as an extension, and restore your browser’s default settings.

Read More

If you’re familiar with my YouTube channel and this blog, you’ll know I’m a big fan of LastPass. Using a password manager, like LastPass, is hands-down the most secure method of implementing secure passwords for all your online accounts. However, you can also use LastPass to store credit card informationYou can use Lastpass to autofill

Read More
how to block a website on mac and pc

You would think that blocking a website would be fairly easy but none of the big four browser offer it as an option.The simplest way to block a specific website is to use a browser extension, such as BlockSite. You can also use the parental controls built into Mac OS and Windows, or a distraction-reducing

Read More