How do I reactivate norton antivirus when I don't know my product key?

u mean reactive???

that mean u had norton anti-virus before....the key should be in ur comptuer

go to Windows folder and

search "Registry"

the key should be there!!

type norton ....to find ur key!!

How do I reactivate norton antivirus when I don't know my product key?nortan antivirus

If you already had it installed on the computer before, hopefully you registered it when you activated it. That means you gave them your name and address and maybe your e-mail. Go to their site and find the customer service 800 number and call them and they can probably find it or at very least give you a new activation number. But always register it so they have proof you bought it originally.

How do I reactivate norton antivirus when I don't know my product key?nortonantivirus

YOu cant, you need to purchase a new one.
Go to their website and buy it. They'll send you a product key.
Call the helpline!