Why won't my MacBook charge or turn on?

I have had my MacBook since new, but stopped using it about 2 years ago. I am wanting to start using it again and I have tried charging it but the light on the charger stays on when plugged in. When I press the power button when plugged in the battery icon and charge symbol show up.

I have tried the charger with my Wife's MacBook Air and it works fine. I have tried cleaning both charger and port. It has been on charge for a few hours with no success.

Any help would be very very much appreciated. TIA