Security Essentials is designed to have a minimal impact on your computer's performance.


Your computer runs more slowly than expected when Security Essentials is running.


Antivirus and antispyware software might cause your computer to slow down, even if the software itself isn't the cause of the slowdown.


Step 1: Verify that your computer has the minimum system requirements for Security Essentials

  • Visit the Security Essentials Web site and check if your computer meets the minimum system requirements stated there. Consider upgrading your computer if it does not meet the requirements or uninstall Security Essentials.

Step 2: Remove any existing security programs

  1. Completely uninstall any existing Internet security programs by following the steps in the topic How do I uninstall antivirus or antispyware programs?

  2. Restart your computer.

  3. Install Microsoft Security Essentials again. If this does not resolve the issue, continue to the next step.

When you remove Internet security programs, your computer is unprotected. If you have problems installing Microsoft Security Essentials after you remove existing Internet security programs, contact Security Essentialsimmediately by submitting a case online. For more information, see How to submit a case online.

Step 3: Install Microsoft Security Essentials

Step 4: Restart your computer

  • Close any open programs and then restart your computer.