Q: Macbook screen stays all white

i turn the mac on you hear the chime but the screen stays white, no spinning circles, nothing. Just a all white screen. I took it to a shop (i have no apple stores in my area) they changed the screen, still nothing. They then said it was the motherboard. Is that one of the symptoms of a bad motherboard? and if they are right and it is the motherboard, is it worth the money to fix or should i just buy a new macbook?