How to Scan Your PC for Viruses & Malware

This guide will take you step by step through the process of deep scanning your entire computer for any kind of virus, malware or spyware, using a free tool provided by Microsoft.

It’s important to note up front – this scan will likely take several hours to complete. The more files on your drive (and the more drives are connected), the longer it will take. The computer will slow down significantly if you try to use it will the scan is happening, so you may want to consider letting this run over night.

1. Head over to the download page for the Microsoft Safety Scanner app. Select the download like for either the 32-bit or 64-bit version of the program (if you’re not sure which to use, check this short guide on how to determine whether you’re using the 32 or 64-bit version of Windows). Once the download has completed, double-click the file to run it.

   If you’re unable to download the file and save it to your local drive, use another computer and download the file to a USB thumb drive. Plug that drive in and run the file from there.

2. There’s nothing to install so the program will start right away. Place a check in the box to acknowledge the license agreement and then click the Next button.
3. Click Next again.
4. Select Full Scan and then click the Next button.
5. Walk away. Seriously, this is going to take hours.
6. When you come back you’ll be presented with a screen letting you know the results of the scan. If anything was found, it will have been removed. Click the View detailed results of the scan link (if it’s present).
7. If you’d like to get more information on any of the things that were found and deleted, simply click the item. A web page will open in your default browser with an overview of the issue.
8. Otherwise you probably got the ‘all clear’ screen. Click Finish
9. The downloaded file will only work for 10 days. After that it’s considered ‘out of date’ and will need to be re-downloaded.

You really should be using something like Windows Defender Antivirus (or Microsoft Security Essentials if you’re using Windows 7) all the time – it’ll help avoid issues in the future.