There are many preventive steps you can take to help protect your PC from viruses and other threats.
Use Windows Defender. Windows Defender is free antimalware software that can help defend your PC against viruses and other malware (malicious software). It scans for viruses, spyware, and other malware trying to get into your email, operating system, or files.
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. Windows Update makes sure that Windows downloads and installs these updates automatically. For more info, see Windows automatic updating: Frequently asked questions.
Use your Internet browser's privacy settings. Being aware of how websites might use your private info is important to help prevent 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.