The Security Center is currently unavailable because the "Security Center" service has not started or was stopped. Please close this window, restart the computer (or start the "Security Center" service), and then open the Security Center again.
Since the Security Center has not been working, it also takes much longer than usual for Windows to start-up.
Before this problem I had been experimenting with disabling certain Startup Items in the Windows Configuration Utility but I have changed these back to the previous settings.
Please advise on this problem,