My suggestions:
First - Remove McAfee (completely). Many have found that this program (and Norton) are not as affective as other products at finding and removing viruses/malware and cause your system to run super slow because they take up SO much of your systems resources.
Second - download
AVG Free anti-virus. It is very effective at protecting your computer and does not take up much of your system resources at all.
Third - download
Malwarebytes. It is free and is very effective at removing malware/spyware/viruses that many other programs do not catch.
Fourth - download
CC Cleaner. This program is effective in cleaning/fixing registry errors and cleans out your system temporary files/cache.