When I installed webroot it shut down windows defender. I have windows 10. I want to turn it on

Hello seeberjudith,
 
Welcome to the Webroot Community,
 
Windows 10 will not allow you to have both Windows Defender and Webroot enabled at the same time. This is a function of Windows, not Webroot. The same will be true of any AV you install on Windows 10.

If you had Windows Defender active at the time you installed Webroot, Webroot will have become the active AV software, and Windows will have automatically disabled Windows Defender. In the event that Webroot is disabled or uninstalled, Windows will automatically re-enable Windows Defender and keep it turned on until you enable or re-install Webroot.
 
But if you want to look here at this KB Article it will tell you how to run Windows Defender.
 
IMO you only need Webroot for full priotection which far surpassess WD.
 
 
Hope this helps,