Should I use more than one antivirus program?

You don’t need to install more than one antivirus program. In fact, running more than one antivirus program at the same time can cause conflicts and errors that make your antivirus protection less effective or not effective at all.

Windows 7 and Windows Vista include spyware protection called Windows Defender. To help fight both viruses and spyware, you can download Microsoft Security Essentials at no cost. If you download Microsoft Security Essentials, Windows Defender will be disabled automatically. Make sure to uninstall any other antivirus software (whether you installed it or it came preinstalled) on your computer first.

Windows 8 includes antivirus and antispyware protection called Windows Defender. Windows Defender for Windows 8 replaces Microsoft Security Essentials. It runs in the background and notifies you when you need to take specific action. If you install a different antivirus program, Windows Defender will be disabled automatically. 

Note: You might see a warning that Microsoft Security Essentials has been turned off because you have other antivirus software on your computer that automatically turns off Microsoft Security Essentials. This type of warning could also be a fake virus alert that attempts to fool you into downloading malicious software. For examples of such rogue security software, see our Real vs. Rogue Facebook app.

For more information, see How to boost your malware defense and protect your PC.

About the Author
Eve Blakemore

Group Manager, Trustworthy Computing

Eve Blakemore is a Group Manager for Trustworthy Computing who delivers consumer guidance around the latest trends in security and privacy. Eve joined Microsoft in 1998 and has worked in corporate and field roles with Microsoft Learning, US Public Sector, Read more »

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  1. Anonymous

    Windows Defender is disabled because I keep getting message to actie it.

    I got the computer from Microsoft Store. Why would they disable the Windows Defener?

    How do I turn it on?

    There is no start menu,which is why can not turn it on. Should I return Windows 8 to the store?

  2. Anonymous

    I have a program called "PC Power Speed" now on my computer which I did not ask for.  I called the telephone number listed and asked them to remove it.  The person I talked to became nasty and when I said I was going to close the computer, he stated "no, I won't let you shut it down."  We actually had a battle to see whether I could shut down or whether he would continue to invade my space.  It interferes with all my work and even when I shut down.  I don't know how to lose this.  Is this a virus?  

  3. Anonymous

    I have Kasperskiy Small Business. Somehow Windows Defender downloaded on to my computer I do not need it. When I check it, it reads "off" I recently got a new Epsom 3520 printer to replace my old Epsom 633 printer. Windows now runs very slow and I get an error message about my Epsom 3 monitior. The message does not stay on long enough for me to read all if it. How do I get rid of Winoows Defender.

  4. Anonymous

    Nope using two antivirus will never be helpfull to your system. it would collide with each other and make your system to cause some problems , so i would suggest you to go with a single antivirus that would suit the features of your system, There are many antivirus softwares which are both available for free and paid. Some are Comodo, Avast, kaspersky etc.

  5. Anonymous

    This is a very important information for internet users.

    Thank u.

  6. Anonymous

    why is security centere asking for virus protection when Microsoft Security Essentials is activated and functionnning.

  7. Anonymous

    Antivirus software is a computer program that detects, prevents, and takes action to disarm or remove malicious software programs, such as viruses and worms. You can help protect your computer against viruses by using antivirus software, such as Microsoft Security Essentials.

    Computer viruses are software programs that are deliberately designed to interfere with computer operation; record, corrupt, or delete data; or spread themselves to other computers and throughout the Internet.

    To help prevent the most current viruses, you must update your antivirus software regularly. You can set up most types of antivirus software to update automatically.

  8. Anonymous

    I added Kaspersky when I bought this computer London Drugs issue of Certified Data) but didn't realize it came with another antvirus/antispyware program. I should get rid of one of them, but doesn't seem that easy to do.

  9. Anonymous

    Someone has entered my computer and is sending e-mails to all my contacts?

    How do I solve this?

  10. Anonymous

    I have VISTA. I used to use Win. Defender regularly. Hwvr, I alsp bought a McAfee pkg that included a security scan. The McA sec. scan works well. The Defender doesn't. With the Defender, after about an hour, it freezes-up, goes blue screen, shuts down, then restarts saying: "Win has rcvrd from an unexpected shutdown…etc, "  Anyone have any thoughts re what to do, what to du?   ps: I am far from being a techie, nerd, even a journeyman operator.

  11. Anonymous

    Never use 2 at the same time but always use a free scanner or malware bytes to check. There is no one ant-virus that will get them all 100% of the time.

  12. Anonymous

    Does Malawarebytes complement Microsoft Security Essentials…. or do they compromise each other ? PS I'm running Windows 7

  13. Anonymous

    I use Vista and MS Essentials, but I also use Panda Cloud Antivirus, Essentials never stopped their antivirus and I'm not having any conflicts that I know of.  According to Panda there shouldn't be any conflicts since they operate in the cloud instead of in the computer.  Am I goobering up my computer without knowing it?

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