Dead Dell Inspiron 3700

Hi, i am having trouble with a dead powerless dell laptop, its an inspiron 3700, the charger i have lights up fine but i can get no power into the laptop itself, no lights nothing, the fan doesnt even start up, could it be a dead switch? or plug? or even the charger lead or head/socket worn out? ....any suggestions would be greatfully received thanks in advance

Pete