Heres an idea, dont know if it will work.
Try disabling Security Center then restart your PC, then enable security center again.
Right click my computer > manage
A window will pop up. Expand Services and applications
Now click on services
Find security center, right click it and select properties
Choose start up type to disable.
Restart PC.
Then follow the same steps again but choose start up type to automatic. And click on start to resume the service.