Can you upload a screenshot of this message?
I agree with others, you probably have some malware or virus on your system. What are the names of the things reported? What action does the popup want you to take? Could be a more passive type of ransomware, a 3rd party malware masquerading as an anti-virus, showing false positive, fake alerts, trying to get you to send money to them (not really McAfee).
An anvi-virus would tend to isolate the suspect files in a folder and exclude them from further reports, so it is only a one time event, unless it can't get rid of what it finds, or can't find something that stays resident and keeps re-downloading more malware. If something keeps re-downloading more malware then the system needs to stay off the internet till completely cleaned, and then you might look at suspicious processes in task manager.
Silly question but does the notice state it is from McAfee? Chrome browser also does malware scans, even if you don't want it to, even if you try to stop it from doing them, sometimes even if you have closed Chrome! There are ways to stop Chrome from doing the scans, but it's a cat and mouse game. They have taken countermeasures to prevent online tutorials from disabling that.
All else fails, do a clean windows install. I'd just do it from the HP partition image backup, if it puts bloatware on, that is removable in Programs/Features (add/remove), or whatever your version of windows is calling it.
