Did you buy this laptop new from Dell with Windows 10? You say that it automatically activated. Did you confirm that in Settings | Activation? If you did and it said it was activated with digital license, you can contact Microsoft for support. There is a link on the activation page. I’m not in front of a computer now, so I can’t check details, but there is a link you click when you cannot activate, to submit information and learn how to contact MS. 
Guys do you know where can i find the product key in the bios?
Windows