First if you don't mind try uninstalling McAfee completely from your computer, use the programs and features applet in the control panel followed by the vendor specific
proprietary removal tool and then see if you can install
Link Removed due to 404 Error and run a full scan.
See if that makes any difference at all in whether or not you can open the security center.
The keys are found by using the registry editor (exactly in the HIVE location I described above) as well as methods to export and import same. Please do not attempt to edit the registry if you are not confident in doing so, as you may make the problem worse instead of better. If you would like to export that particular key (if present) zip it up and attach it to...