The trouble with multiple posts is that you may end up with multiple answers or none at all so best not to do that.
If these troubles seem to coincide with an upgrade the chances are the upgrade wenr badly for whatever reason.
First thing to do is make sure your system clock is accurate both time and timezone-wise and that your system is totally up to date, including IE, even if you don't use it, McAfee does.
Go to Control Panel > Programs and Features and uninstall all McAfee.
Then run the MCPR cleanup tool and reboot.
Run the McPreinstall Tool.
Reinstall from your online account NOT from any CD.