Answer to: What can I charge my nextbook with?Looks like this should do the trick! Make sure you compare with the pictures to check that it will work! https://www.amazon.com/Listed-Charger-Adapter-Nextbook-Ares-Tablet/dp/B008FSX2SQ/ref=sr_1_4?s=electr...-4&keywords=Nextbook+Flexx+adapter
Answer to: Why back will not seat fully?The way the keyboard is constructed, it shouldn't have been affected by this repair in any way, that's really weird! The keyboard is held into the frame by 80-some screws and rivets, which you wouldn't have been able to even get near to while following that guide. The flex on the bottom could be due to those clips, sometimes the two clips in the center of the base will break or won't engage properly.