Does it turn on with the original battery connected? Or did it ever?
Try this, install display with new battery, wait 15 seconds, that's about as much time as it needs to boot up all the way, after 15 sec, turn the vibrator button on and off, and if you don't feel a vibration, battery is bad, if you do feel a vibration, lcd screen is bad. Try a new battery, if new battery doesn't work, check by the battery connectors you will see some small components closest to the connector, you might have broke off one of those components while prying the battery up. I've done that before and it's not easy to deal with if you dont have micro soldering experience. If that is the case try to find a repair shop around you that has micro soldering experience with this issue. Always disconnect the battery from the left side of the connector with a spudger under the flex cable. Hope this helps.