Why won't my Kindle Fire let me register?

Alright, so I know all about it. I've been trying to sign into my amazon account so I can access the apps on my brand new tablet but this thing wants to be so complicated and says that my email and password is incorrect or that it is some sort of error. I've changed my password about three times. I surfaced the internet upon tons of people who have the same problem I've had but I couldn't find a solution. I even restarted the entire tablet.This was a Christmas present so it was purchased from the Amazon website. So can someone please, help me with this.