I am running Windows 8.1. The defender is red and will not turn on. The box that turns it on/off is checked, but it stays red and asks to be turned on. I

ran the update and it did do that. I ran a quick scan and it did that also.  I'm running a full scan now and it seems to be doing that as well. I know it should be green when turned on, so what could be my problem? I know Microsoft Security Essentials should be turned off when running Windows 8/8.1. I looked for it in task manager to turn it off, but couldn't find it. Can anyone help with this? Thanks.

William D