Your antivirus software - System Center Endpoint Protection - sends automatic definition updates as part of your Windows updates.  When you get notified that you have updates, you should always choose to run any essential Windows updates.   If you aren't receiving notifications of updates, then change your Windows Update settings.

Changing Windows Update Settings

1.  Click on Windows Update from the Control Panel.

2.  Click on Change settings from the menu on the left.

3.  The Choose how Windows can install updates window will open.  Make sure that the Install updates automatically option is chosen under the Important updates section.  In the Install new updates: field choose Every day.   The time should be set at a convenient time for you.  If you eat lunch at noon most days, 12:00 p.m. would be a good time so that there will be no interruption to your work.  The default is 3:00 a.m., but if your machine is shut down at night, that won't work.  When you have finished, press the OK button.

System Center Endpoint Protection

If your Windows updates are all set, but you still want to check to make sure that you have the latest antivirus definitions, you can check for updates at any time.

  1. Open System Center Endpoint Protection in your applications list.

2.  Press the Updates tab.   On this tab you will see when the definitions were last updated.  You can click on the Update button if you think that your definitions are out-of-date, and the application will check for the latest definitions.