windows security center is turned off

Issue 1: 

security center service can't be started

Solution: 

Issue 2: 
can't turn on windows firewall  under security center

Solution:

http://support.microsoft.com/kb/920074

http://www.thewindowsclub.com/windows-firewall-service-does-not-start

http://www.sevenforums.com/system-security/253751-windows-firewall-service-won-t-start.html

Configuring the Registry: Disabling APIPA

Use Registry Editor to create the following registry key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

Add the following value to this key:

Value name: IPAutoconfigurationEnabled Value type: REG_DWORD Value in hexadecimal: 0 (A value of 0 disables APIPA support on this computer)

NOTE: If the IPAutoconfigurationEnabled entry is not present, a default value of 1 is assumed, which indicates that APIPA is enabled.

After you make this change, restart your computer.

If routing is still not functioning properly, you may have to repair the connection:

1. Right-click the LAN connection icon in Network Connections, and then click Status.

2. Click the Support tab, click the Repair button.