Hello my name is ***** ***** certified computer professional with over 10 years experience. I will be happy to help you.
I am sorry to hear what happened.
You cannot install Mcafee on a Chromebook. Chromebooks are not like windows or mac computers and everything that can be installed is done through the gogle app store. As for viruses I do not think you are a traditional windows type virus but there could be something wrong with the computer.
What I would suggest is you look over this article and perform a reset of the chromebook. Since the chromebook saves everything online a reset should get it back in working order without you loosing anything.
Have a look here https://support.google.com/chromebook/answer/3438631?hl=en
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