My Win 8 PC came with McAffee anti-virus. Windows defender is showing on the start screen, but when clicked a pop up window states: "Windows Defender has been turned off and isn't monitoring your computer. If you are using another app to check for malicious software use Action Center to check that app's status."
The other app (McAffee) started giving error indicators that that couldn't be handled, so I removed that software. Even with McAffee removed I still cannot get Windows Defender to start. Also, although Windows Defender shows up on the start screen, there is no such program showing in the Control Panel "Programs and Features".
I thought I would re-install Windows Defender, but don't find a version for Windows 8.
Also, where is the "Action Center?