Why wont iPod touch 6 boot up?

I have ipod touch 6th gen (iPod 7.1; M/N-A1574). I found that the battery was bad a few months ago... device slowly did not last as long while not plugged in. Until it suddenly died. Then I could leave it plugged in to use. However, one day I plugged it in and the seemed as though to power on, I saw the White screen with the "Apple Logo" but then the screen goes black, although you can plainly tell that the backlight is still lit, it's that faint dark graish blue glow especially with the room lights off. Anyway it would not pass that point and finish fully booting up.

I installed a new battery, following the guide from this site. Now the same problem exsists, although I am confident that the battery was bad and now the newly installed battery is charging. Because I don't have to have it plugged in to encounter the same boot up issue I am having. I now experience the same boot up issue when plugged in and when attempting to boot up while unplugged, so the new battery fixed one issue. Now makes it apperent that I had more than just one issue.

Can anybody please shed any light on my current issue or assist in repairing, such as a guide or proccess?