Help prevent viruses from getting on your PC
There are many preventive steps you can take to help protect your PC from viruses and other threats.
Use an antimalware app. Installing an antimalware app and keeping it up to date can help defend your PC against viruses and other malware (malicious software). Antimalware apps scan for viruses, spyware, and other malware trying to get into your email, operating system, or files. New threats can appear daily, so check the antimalware manufacturer’s website frequently for updates.
Windows Defender is free antimalware software included with Windows, and you can update it automatically through Windows Update. You can also visit the list of Consumer security software providers to look for antivirus apps that work with Windows.
Don’t open email messages from unfamiliar senders, or email attachments that you don’t recognize. Many viruses are attached to email messages and will spread as soon as you open the attachment. It’s best not to open any attachment unless it’s something you’re expecting.
Use a pop-up blocker with your Internet browser. Pop-up windows are small browser windows that appear on top of the website you’re viewing. Although most are created by advertisers, they can also contain malicious or unsafe code. A pop-up blocker can prevent some or all of these windows from appearing. Pop-up Blocker in Windows Internet Explorer is turned on by default. For more info, see Change security and privacy settings in Internet Explorer.
If you’re using Internet Explorer, make sure SmartScreen Filter is turned on. SmartScreen Filter in Internet Explorer helps protect you from phishing and malware attacks by warning you if a website or download location has been reported as unsafe. For more info, see SmartScreen Filter: FAQ.
Pay attention to Windows SmartScreen notifications. Be cautious about running unrecognized apps downloaded from the Internet. Unrecognized apps are more likely to be unsafe. When you download and run an app from the Internet, SmartScreen uses info about the app’s reputation to warn you if the app isn’t well-known and might be malicious.
Keep Windows updated. Periodically, Microsoft releases special security updates that can help protect your PC. These updates can help prevent viruses and other malware attacks by closing possible security holes.
You can turn on Windows Update to make sure that Windows receives these updates automatically.
Use a firewall. Windows Firewall or any other firewall app can help notify you about suspicious activity if a virus or worm tries to connect to your PC. It can also block viruses, worms, and hackers from trying to download potentially harmful apps to your PC.
Use your Internet browser’s privacy settings. Some websites might try to use your personal info for targeted advertising, fraud, and identity theft.
If you’re using Internet Explorer, you can adjust your privacy settings or restore the default settings whenever you want. For more info, see Change security and privacy settings in Internet Explorer.
Make sure User Account Control (UAC) is turned on. When changes are going to be made to your PC that require administrator-level permission, UAC notifies you and gives you the chance to approve the change. UAC can help keep viruses from making unwanted changes. To open UAC, swipe in from the right edge of the screen, and then tap Search. (If you’re using a mouse, point to the upper-right corner of the screen, move the mouse pointer down, and then click Search.) Enter uac in the search box, and then tap or click Change User Account Control settings.
Clear your Internet cache and your browsing history. Most browsers store info about the websites you visit and the info that you provide, like your name and address. While it can be helpful to have these details stored on your PC, there are times when you might want to delete some or all of them—for example, when you’re using a public PC and don’t want to leave personal info behind. For more info, see Delete your browsing history.
Security checklist for Windows
Take advantage of all the ways you can help keep your PC safer and more secure with Windows.
The Action Center icon.
Action center. Check Action center to make sure your firewall is on, your antimalware protection is up to date, and your PC is set to install updates automatically.
The Windows Defender icon.
Windows Defender. Use Windows Defender to help prevent viruses, spyware, and other malicious or unwanted software from being installed on your PC without your knowledge.
Administrator password needed icon.
Windows SmartScreen. Use Windows SmartScreen to help protect your PC by warning you before running unrecognized apps and files downloaded from the Internet.
Administrator password needed icon.
User Account Control. Make User Account Control ask for permission before your PC installs software or opens certain kinds of apps that could be potentially harmful or make it vulnerable to security threats.
The File History icon.
File History. Use File History to regularly back up your personal files—like photos, documents, and music—automatically. If your PC has a hardware failure, you can restore any versions of the files that are most important to you.
The Windows Update icon.
Windows Update. Use Windows Update to automatically download and install the latest updates for your PC.
The Windows Firewall icon.
Windows Firewall. Turn on Windows Firewall to help prevent hackers and malicious software, such as viruses, from accessing your PC through the Internet.
Stay informed about the latest security issues
Security updates for Windows can help protect against new and ongoing threats to your privacy and to your computer.
To learn about new security updates, find how-to articles and security tips, and get answers to security-related questions, go to the Microsoft Security at Home website.
To learn how Microsoft monitors and responds to security issues, go to the Microsoft Security Response Center website.
Update your antivirus software
Antivirus software must be updated regularly to stay effective against new viruses. Most antivirus software is designed to update automatically, but you can also update your software manually.
Windows doesn’t come with antivirus software, but it can often detect and monitor antivirus software that was installed by you or your computer manufacturer. The status of your antivirus software is typically displayed in Action Center.
Open Action Center by clicking the Start button Start button icon, clicking Control Panel, and then, under System and Security, clicking Review your computer’s status.
Click the arrow button next to Security to expand the section.
If Windows can detect your antivirus software, it will be listed under Virus protection.
Click Update now.
Turn Windows Firewall on or off
Open Windows Firewall by clicking the Start button Start button icon, and then clicking Control Panel. In the search box, type firewall, and then click Windows Firewall.
In the left pane, click Turn Windows Firewall on or off. Administrator icon If you’re prompted for an administrator password or confirmation, type the password or provide confirmation.
Click Turn on Windows Firewall under each network location that you want to help protect, and then click OK.
If you want the firewall to prevent all programs from communicating, including programs that you have previously allowed to communicate through the firewall, select the Block all incoming connections, including those in the list of allowed programs check box.