I hope you mean 512mb Just fire it up like any computer. No special testing procedures should be needed.
My OLD Carputer: http://www.mp3car.com/node/18137
Currently, Don't have a carputer :( I sold my lincoln and bought a '93 Acura Vigor, plan on putting a carputer in it one of these days. You can see my vigor at: This Site
feel free to plug a normal ATX power supply into it for indoor testing purposes, if your normal power supply is DC-DC...other than that, have fun! Be sure to connect it to a VGA monitor to start with, you have to install some stuff to configure the LCD.