Canonsveg

I have a 2006 is350 with 150,000miles and I bought the car and the infotainment system wouldn't turn on. The radio and aux portion works but the navigation part wont come on. Sometimes very rarely it'll come on and work for about 1 min then freeze up and sometimes black out or keep getting whiter and whiter till it blacks out. Do I need to replace the whole system or is a wiring problem In the car etc??
Thanks