Unexpected system crashes and BSOD (Blue Screen of Death). Your web browser keeps getting redirected to pages you didn’t click. You see apps and toolbars that you didn’t install. You see pop-up windows claiming you must pay money or bitcoin to regain access to your files. Random network activity with heavy bandwidth usage. You see a pop-up that says you have to download some file to fix an issue on your computer. Your computer is running extra slow for no good reason with excessive hard drive activity. Apps, tools and antivirus on your computer are disabled (or you get an error when trying to run them). When using a browser, your computer redirects to a webpage. Your browser opens randomly and you didn’t open it.
Click Check for updates under the “Virus & threat protection updates” header near the bottom. Click the Check for updates button on the next screen. When the process is finished, the “Last update” date should reflect the current date and time.
Windows Defender is set to protect your computer automatically by default. If threats have already been detected, follow the on-screen instructions under “Current threats” to get rid of the malware.
Use this article on How to Perform an Offline Scan with Windows 10 Defender.
If no threats were found, there’s no need to continue with this method.
If malware was found, Windows Defender will usually quarantine it automatically. You’ll see the name of the malware under the “Quarantined threats” header.
Use this method if you are unable to run a scan or update your anti-malware tool. You can also use this method if your usual anti-malware tool failed to fix the issue. If you can’t use a web browser or connect to the internet on the infected PC, download the tool to a working computer, follow the download steps on a working computer. You can then copy or burn the tool to removable media and insert that into the infected PC.
If you see a screen that displays recommended downloads, remove the check marks from each download, then click No thanks and continue to DirectX End-User Runtime Web Installer at the bottom-right corner.
USB drive: Connect the drive to the PC, then copy the tool (the file that begins with “Windows-kb” and ends with “. exe”) to it from the Downloads folder. CD/DVD-ROM: If the infected computer has a CD/DVD-ROM drive, you can burn the tool to a disc instead.
If the malware prevents you from running the tool, you’ll need to run the tool in Safe Mode. Follow these steps to reboot into Safe Mode, then try again: Click the Start {“smallUrl”:“https://www. wikihow. com/images/0/07/Windowsstart. png”,“bigUrl”:"/images/thumb/0/07/Windowsstart. png/30px-Windowsstart. png",“smallWidth”:460,“smallHeight”:460,“bigWidth”:30,“bigHeight”:30,“licensing”:"<div class="mw-parser-output">
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Hold ⇧ Shift as you click Restart.
Navigate to Troubleshoot  Advanced Options and click Restart.
Press 4 or F4 at the menu to enter Safe Mode.
If these steps don’t work, see Activate Safe Mode in Windows 10.
If the malware prevents you from running the tool, you’ll need to run the tool in Safe Mode. Follow these steps to reboot into Safe Mode, then try again: Click the Start {“smallUrl”:“https://www. wikihow. com/images/0/07/Windowsstart. png”,“bigUrl”:"/images/thumb/0/07/Windowsstart. png/30px-Windowsstart. png",“smallWidth”:460,“smallHeight”:460,“bigWidth”:30,“bigHeight”:30,“licensing”:"<div class="mw-parser-output">
I edited this screenshot of a Windows icon. \n</p>
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Hold ⇧ Shift as you click Restart.
Navigate to Troubleshoot  Advanced Options and click Restart.
Press 4 or F4 at the menu to enter Safe Mode.
If these steps don’t work, see Activate Safe Mode in Windows 10.
Alternatively, you can select Quick Scan to do a short scan of the areas of your computer most likely to contain malware.
No infection was found: The issue may not be malware-related. It’s also possible that the tool hasn’t been updated to include the latest malware. Check the download page frequently for updates (click the “+” next to “Details” to see the date), then re-download the tool once updated. At least one infection was found and removed: Malware was found and successfully removed. Now that you’re in the clear, make sure to update Windows as soon as possible. An infection was found but not removed: This means the PC is infected, but the tool is not equipped to remove it. Try downloading another tool, such as https://www. malwarebytes. com/mwb-download, and running it the same way as you did this one. An infection was found and was partially removed: If you can, try to update and use Windows Defender to finish the job. If that doesn’t work, download another tool, such as https://www. malwarebytes. com/mwb-download and run it the same way as you did this one.
If you want to try a different antivirus, you can look into options like Avast, BitDefender, Malwarebytes, and AVG. Make sure the antivirus/anti-malware definition files are always up-to-date, as new malware is created daily.
Also be wary of websites that offer free templates for download—research the site before downloading these files, as they may be spreading viruses.