My laptop's processor is damaged
My laptop processor is damaged can i replace my motherboard.
and when i replace a motherboard my laptop is properly working or not
If your processor is damaged it can be replaced independent of your motherboard. My experience is the motherboard dies more often than the processor, but your case may be different of course. Especially if heat has been an issue. There is a nice service manual provided here on ifixit.
First things first though. Please describe your symptoms so we can be sure that's your problem.