Radio and LCD turn on and off on 1998 Lexus LS400

I have a 1998 LS400 with the touchscreen LCD. Three days go the screen and radio started to malfunction. The screen and radio will only stay on if the car is idle but if the car is moving it just turns off and on which is annoying. Does anyone know if this is electrical or three computer. Please help me.

Asked by for the 1998 Lexus LS400