im new to this forum but i got a problem with my AVH-P4900DVD touch screen. its brand new, i just got it saturday and it doesnt seem to be working, and neither do any of the buttons on the screen itself, ie the close open button and all the other buttons. does anyone have any ideas on what the problem can be? the guy i got it from said he would change it out but i just wanted to know what could cause this. thanks for any help