I replaced the screen and digitizer but when I tried to power up, nothing happens. I thought it was a low battery issue so I left it charge overnight. Still nothing. I put this battery into another Nexus 7 to see if it is a battery problem. That Nexus booted up and shows the battery at 100%. So the battery did charge as it should. I tried putting the battery from the second Nexus into the first Nexus and It does nothing. I have checked all of my connections several times and everything seems to be fine. It did power up before I replaced the screen and digitizer.Any ideas?