I'm trying to get a computer in my car as cheap as possible. How can I make a remote power button to turn it on?

I want to have navigation watch DVD's play music, turn it on and off remotely, and have it on a touch screen

BTW Would it be able to hook up the laptop to my Eclipse AV8012 Flipscreen (RCA in's and out's)HU? Can I get a touchscreen kit or something?