this is all i could find out from the internet so not sure if this will help you out.
but if you do try this do so at your own risk.
This helps most ppl, get your code.com that's a link nextbooks activation site to get your code(automated) or argue with a rep if you like. :/ Also, the DiSa number they want is your serial number. should be on the back cover, if not, hold volume down and power
buttons on startup til u see the NEXTBOOK logo, then let off power. the next screen that comes up will have it displayed there. Hope that helps..
again i found this on the internet.
or go to this link and have a read up.
Nextbook Ares 8A Activation Code
or this one.
activation code for Nextbook 8a Google Search