Moved to Consumer > General as a better spot for it.
What operating system is it?
First of all make sure your computer is totally up to date.
Uninstall any current McAfee software via Control Panel > Programs and Features, reboot if asked to.
Run the MCPR cleanup tool and reboot.
Go to your online account and install from there.
Could you right click McAfee system tray icon and select "Verify Subscription". Wait until verification is complete and then open the GUI to see if its OK.