Hello,
If you have Windows 8, or Windows 10, I would dump McAfee and just use Windows Defender. McAfee is very bloated and only offers average protection. Windows Defender is very light-weight, fast, and very automatic. Please follow my instructions for how to completely remove McAfee and use Windows Defender in it's place here:
If you have Windows 7, go with Microsoft Security Essentials, it's the same pretty much as Windows Defender. On Windows 8 and Windows 10, Windows Defender is a full anti-virus program. On Windows 7, Windows Defender is a malware blocker only. Users who upgrade to Microsoft Security Essentials on Windows 7 will be automaticllly updated from Windows Defender to MSE. Windows 7 users can download Microsoft Security Essentials here:
https://www.microsoft.com/en-us/download/details.aspx?id=5201 (Only For Windows 7.)
Important; Make sure you completely remove your competing anti-virus program software before installing a competitor. Windows 7 users who download and install MSE will be automatically updated from Windows Defender. But if you have competing AV like Avast, Macafee, Avira, AVG, you must remove that software first through Ad-Remove Programs before installing a different AV program.
Also install Adblock Plus on all your web browsers. Just Google Search for it in each browser and install. It blocks 99% of banner ads and bad links that can have viruses and malware. It even blocks ads in You Tube Videos!
Satch