It needs to be connected to the Internet to activate the software plus to check for updates which occurs every few hours. It also relies on a system that is totally up to date, even parts of the system you may not always or hardly ever use.
Malware can be introduced to a machine that's not connected to the Internet by various means and maybe that other software doesn't check first for malware before running its installer. Not all security software does. Customer Service or Technical Support would direct you to purchase virus removal. All antivirus makers charge for one-on-one virus removal but there are always free alternatives if you do some research, see the last link in my signature below.
You can obtain a refund from Customer Service within 30 days of purchase, or 60 days if it was a subscription renewal. See the link under Useful Links at the top of this page.