Go to Add/Remove programs and uninstall your software and reboot the machine. Then go to Useful Links at the top of this page and use the MCPR removal tool. MCPR removes any remnants of the old installation that fail to completely remove via Add/Remove. Reboot the computer again and then login to your online McAfee account and download your software.
Please let us know this works for you.
Adding to this, if you still face any issues, please provide the following information along with your next post;
What is the operating system ?
How old is the computer ?
Any malware pop ups / virus infections in the computer (or in past)?
Do you have any third party security software installed ?
McAfee Online Community Moderator