Windows 7 Issues Activating Windows Defender: Stuck on "Program is Turned Off

I use Microsoft Security Essentials and Windows Firewall so I thought I would use Windows Defender as well. According to my computer it is not running. When I click on it to start I receive a message "This program is turned off". "If you would like to use this program click here to turn it on". If I click on it nothing happens. All I get is the spinning wheel that doesn't stop. If I check in "services" its startup type is listed as "manual" and its "status" is blank. I tried resetting it to automatic and rebooted but when I come back it hasn't changed. Am I doing something wrong?