Stuck on android logo, can't boot!

[Android Central Question]

Yesterday my old LG v909 tablet just restarted itself and got stuck on the android logo after the lg screen. Nothing helps, i tried to restart it with the butten behind the tablet. I tried taking out the battery to shut it down and turn it back on, which also did not help. I tried after taking the battery out to turn it of , pushing the power butten and volume down butten to factory reset it but this way it just keeps giving me the do not power down, downloading now screen and in the above left corner in little letters says entering LG MDP Mode and it stays like this without any change. What can i possible do? (Note, volume up butten does not work)