The license code for the operating system is going to be on a sticker on the bottom of your computer. You should be able to activate it online, with a smartphone, or with a phone call by using the license code on that sticker. If you follow the prompts for the activate windows popups that keep bothering you, it'll lead you to a website or phone number to call. It takes maybe 10-15 minutes, tops, even if you have to talk to a real person to get it done.