If you connect to the Internet, allow other people to use your computer, or share files with others, you should take steps to protect your computer from harm. Why? Because there are computer criminals (sometimes called hackers or crackers) who attack other people's computers. These people can attack directly, by breaking into your computer through the Internet and stealing your personal information, or indirectly, by creating malicious software (or malware) designed to harm your computer.

Fortunately, you can protect yourself by taking a few simple precautions. This article describes the threats and what you can do to defend against them.

Check your security status with Windows Security Center

Windows Security Center is your headquarters for computer security. It shows your computer's current security status and recommends anything that you should do to help make your computer more secure. To open it:

  • Open Security Center by clicking the Start button Picture of the Start button, clicking Control Panel, clicking Security, and then clicking Security Center.

Security Center checks your computer for these security essentials:

  • Firewall. A firewall can help protect your computer by preventing hackers or malicious software from gaining access to it.

  • Automatic updating. Windows can routinely check for updates for your computer and install them automatically.

  • Malware protection. Antivirus software can help protect your computer against viruses, worms, and other security threats. Antispyware software can help protect your computer from spyware and other potentially unwanted software.

  • Other security settings. Security Center checks for proper Internet security settings and whether User Account Control is turned on. For more information, see User Account Control Overview.

Picture of Windows Security Center
Windows Security Center

If any of the security items have a red or yellow background, your computer might be vulnerable to security threats. To fix the problem, click an item to expand it, and then follow the instructions.

What are security alerts?

If Windows detects that your computer might need enhanced security in any one of the security areas—firewall, automatic updating, malware protection, or other security settings—you will see a notification every time you log on until the problem is fixed. Notifications are displayed in the notification area of the taskbar.

Picture of a security notification
Security notification

Click the notification to open Security Center, where you can learn how to fix the problem.


  • To turn off security notifications or hide the Security Center icon in the notification area, open Security Center, click Change the way Security Center alerts me, and then choose an option. Even if you turn off notifications, Security Center will continue to check and display security status.

Use a firewall

A firewall is software or hardware that checks information coming from the Internet or a network and then either turns it away or allows it to pass through to your computer, depending on your firewall settings. In this way, a firewall helps prevent hackers and malicious software from gaining access to your computer.

Windows Firewall is built into Windows and is turned on automatically.

Illustration of how a firewall works
How a firewall works

If you run a program such as an instant messaging program or a multiplayer network game that needs to receive information from the Internet or a network, the firewall asks if you want to block or unblock (allow) the connection. If you choose to unblock the connection, Windows Firewall creates an exception so that the firewall won't bother you when that program needs to receive information in the future.

See also Firewall: frequently asked questions.

Use virus protection

Viruses, worms, and Trojan horses are programs created by hackers that use the Internet to infect vulnerable computers. Viruses and worms can replicate themselves from computer to computer, while Trojan horses enter a computer by hiding inside an apparently legitimate program, such as a screen saver. Destructive viruses, worms, and Trojan horses can erase information from your hard disk or completely disable your computer. Others don't cause direct damage, but worsen your computer's performance and stability.

Antivirus programs scan e‑mail and other files on your computer for viruses, worms, and Trojan horses. If one is found, the antivirus program either quarantines (isolates) it or deletes it entirely before it damages your computer and files.

Windows does not have a built-in antivirus program, but your computer manufacturer might have installed one. Check Security Center to find out if your computer has antivirus protection. If not, go to the Microsoft Antivirus Partners webpage to find an antivirus program.

Because new viruses are identified every day, it's important to select an antivirus program with an automatic update capability. When the antivirus software is updated, it adds new viruses to its list of viruses to check for, helping to protect your computer from new attacks. If the list of viruses is out of date, your computer is vulnerable to new threats. Updates usually require an annual subscription fee. Keep the subscription current to receive regular updates.


  • If you do not use antivirus software, you expose your computer to damage from malicious software. You also run the risk of spreading viruses to other computers.

See also Viruses: frequently asked questions.

Use spyware protection

Spyware is software that can display advertisements, collect information about you, or change settings on your computer, generally without appropriately obtaining your consent. For example, spyware can install unwanted toolbars, links, or favorites in your web browser, change your default home page, or display pop-up ads frequently. Some spyware displays no symptoms that you can detect, but it secretly collects sensitive information, such as which websites you visit or text that you type. Most spyware is installed through free software that you download, but in some cases simply visiting a website results in a spyware infection.

To help protect your computer from spyware, use an antispyware program. This version of Windows has a built-in antispyware program called Windows Defender, which is turned on by default. Windows Defender alerts you when spyware tries to install itself on your computer. It also can scan your computer for existing spyware and then remove it.

Because new spyware appears every day, Windows Defender must be regularly updated to detect and guard against the latest spyware threats. Windows Defender is updated as needed whenever you update Windows. For the highest level of protection, set Windows to install updates automatically (see below).

See also Spyware: frequently asked questions and Using Windows Defender.

Update Windows automatically

Microsoft regularly offers important updates to Windows that can help protect your computer against new viruses and other security threats. To ensure that you receive these updates as quickly as possible, turn on automatic updating. That way, you don't have to worry that critical fixes for Windows might be missing from your computer.

Updates are downloaded behind the scenes when you're connected to the Internet. The updates are installed at 3:00 A.M. unless you specify a different time. If you turn off your computer before then, you can install updates before shutting down. Otherwise, Windows will install them the next time you start your computer.

To turn on automatic updating

  1. Open Windows Update by clicking the Start button Picture of the Start button, clicking All Programs, and then clicking Windows Update.

  2. Click Change settings.

  3. Make sure Install updates automatically (recommended) is selected. Windows will install important updates for your computer as they become available. Important updates provide significant benefits, such as improved security and reliability.

  4. Under Recommended updates, make sure the Include recommended updates when downloading, installing, or notifying me about updates check box is selected, and then click OK. Recommended updates can address non-critical problems and help enhance your computing experience. Administrator permission required If you are prompted for an administrator password or confirmation, type the password or provide confirmation.

See also Understanding Windows automatic updating.

Use a standard user account

When you log on to your computer, Windows grants you a certain level of rights and privileges depending on what kind of user account you have. There are three different types of user accounts: standard, administrator, and guest.

Although an administrator account provides complete control over a computer, using a standard account can help make your computer more secure. That way, if other people (or hackers) gain access to your computer while you are logged on, they can't tamper with the computer's security settings or change other user accounts.

To determine your account type

  • Open User Accounts by clicking the Start button Picture of the Start button, clicking Control Panel, clicking User Accounts and Family Safety (or clicking User Accounts, if you are connected to a network domain), and then clicking User Accounts.

    The account type appears under your name.

    Picture of user account information
    User account information

If you are currently using an administrator account, see Change a user's account type to learn how to change it to a standard account.

See also User accounts: frequently asked questions.

Tips for using e‑mail and the web safely

  • Use caution when opening e‑mail attachments. e‑mail attachments (files attached to e‑mail messages) are a primary source of virus infection. Never open an attachment from someone you don't know. If you know the sender but were not expecting an attachment, verify that the sender actually sent the attachment before you open it. See When to trust an e‑mail message and Avoiding e‑mail viruses.

  • Guard your personal information carefully. If a website asks for a credit card number, bank information, or other personal information, make sure that you trust the website and verify that its transaction system is secure. See When to trust a website.

  • Use the Phishing Filter in Internet Explorer. Phishing is the practice of creating fraudulent e‑mail messages and websites in order to trick computer users into revealing personal or financial information. The fraudulent e‑mail message or website appears to be from a trusted source, such as a bank, credit card company, or reputable online merchant. The Phishing Filter helps detect phishing websites to protect you from scams. See Phishing Filter: frequently asked questions.

  • Be careful when clicking hyperlinks in e‑mail messages. Hyperlinks (links that open websites when you click them) are often used as part of phishing and spyware scams, but they can also transmit viruses. Only click links in e‑mail messages that you trust.

  • Only install add-ons from websites that you trust. Web browser add-ons, including ActiveX controls, allow webpages to display things like toolbars, stock tickers, video, and animation. However, add-ons can also install spyware or other malicious software. If a website asks you to install an add-on, make sure that you trust it before doing so. See Should you install ActiveX controls? and Internet Explorer add-ons: frequently asked questions.