This sometimes happens after running registry cleaners and optimizers which I don't recommend. If you have run one see if it has a restore button.
It can also happen with certain types of malware so check this required reading: http://community.mcafee.com/docs/DOC-1294
Try downloading, updating and running the free version of THIS software. Let it remove everything it finds and reboot when asked to, if asked to of course.
If, after all that, there is no change then try uninstalling all McAfee software the normal way, Control Panel/ Programs/Uninstall a Program.
Then run the MCPR removal tool listed under Useful Links above and reboot.
Reinstall your software from your online account.