Rather than rehash an old thread where the conditions have probably changed drastically over the months/years I've moved you to your own thread.
If you upgraded to a newer version the problem may be that the old software needed to be totally removed first.
Try uninstalling via Control Panel, then run the MCPR cleanup tool listed under Useful Links at the top of this page, reboot and reinstall from your online account.
Also make sure that your operating system is totally up to date and for McAfee purposes that Internet Explorer is up to date and at default settings but it doesn't have to be your default browser.
I meant to add, if the above doesn't help then contact Technical Support direct as it's free by phone or online chat and they can troubleshoot it much easier than I. They are linked under Useful Links also.
They weren't any help at all.
Time to switch to a competitor.....
A complete uninstall/cleanup/reinstall didn't help?
That's too bad, good luck.