Laptop...No Internet Security...Now has Malware

Dear Forum:
Unusual situation with laptop. Laptop was in storage.
Upon removing from storage had Cox Cable come out to set up internet connection. A new tech came out.
I forgot Cox offered McAfee Security Suite with service.
Tech did not inform me to download.
Laptop was kept shut off.
Recently tried to download McAfee onto laptop. Now it appears it has Malware.
How do I maintain my internet connection; clean out the laptop; and download McAfee?
I am somewhat a novice.
Thank You...