Hi Dannie...welcome to the forum. I had to move your post because you put it in the new member introduction thread when this is really a question for help...thus i moved it to the help thread. When you get a chance you can leave a proper intro in that thread if you feel so inclined but all questions need to be in the appropriate board.
As for your Nexus 7 not turning on have you made sure that the charging connector is pushed all the way in until it clicks, and that of course the wall outlet you are plugging it into is actually working. Both need to be checked to make sure the N7 is getting power and while it might sound silly one or the other is often the culprit in not charging a dead battery. After you've made sure your device is actually receiving power from the charger, have you tried doing a soft reset on your device by holding down the power button for about 8 to 10 seconds and then releasing it?