I edited your post as such a huge header causes problems with the search function.
What is your operating system and service pack? (Right-click My Computer (XP) or Computer (Vista/Windows 7) and select Properties and post that information.
Go to your Control Panel/Add or Remove Programs (XP) or Programs/Uninstall a Program (Vista/Windows 7) and uninstall all McAfee entries.
Then run the MCPR removal tool listed under Useful Links above. Reboot immediately when asked.
Go to your online account and reinstall your product.
don't you think that it is only a problem with a hidden icon? May be with a click on the little arrow beside the language notification, you can see McAfee icon? It happened here!
With a right click on the task bar, then properties, notifications... etc...I don't really know the way in english, but it often happens that icons disapeared only by the instability of Windows...
It's worth a try I suppose, actually that is so simple it escaped me I hate to admit...LOL!!
What operating system and service pack is this by the way?