I'm sorry about the issue. That is a scam. Please do not purchase anything; please just close it / cancel it. Do not use any program / website that you do not know. If you are able to use your computer fine, then you do not need to do anything. But if there is popup issue, i.e., when you use the Internet, then download / install the free Malwarebytes Anti-Malware software at the website below, then use it to scan / fix your computer:
; (only use the free version, do not purchase anything.)
Do you have any other computer question / issue?
Please reply at the box below to continue troubleshooting. Thank you.