When you buy a computer, the operating system software installed on it comes licensed, for at least the life of the computer. That is part of the price you paid for the computer. That said, if you receive a pop up or phone call trying to scare you into thinking yours has expired - IGNORE IT!
You will need to find the adware or malware that installed this, remove it and clear your browser cache and history. I also recommend running Malwarebytes AdwCleaner.
Contact BSCANS if you need help.