Have you seen this link regarding malware?Required Reading - Home User Assistance Malware Troubleshooting Maybe there is something additionally you could do based on those recommendations.
You could also try to run SuperAntispyware www.superantispyware.com which is free and removes a lot of spyware which may be on the machine. You might need to download this to a usb stick and rename the download to something you can easily remember as well as the installation folder. After it is installed check for updates and run the program and let it clean everything it finds and then reboot the computer.
I would suggest you do the same for Malwarebytes www.malwarebytes.org with respect to the renaming of the download and install files. You should remove SuperAntivirus as it is probably conflicting with McAfee since McAfee is an antivirus program.
Another sugeestion would be to uninstall via Add/Remove programs and reboot, then go to Useful links at the top of this page and run the MCPR removal tool. MCPR will remove any traces of McAfee leftover that fail to remove via the normal uninstall and reboot again. Then login to your online McAfee account and download and install your software and see if problem gets corrected.
Let us know how this works for you.