The light in the Ac adapter is lit when not connected to the laptop but when it is insertd to the laptop the light on the adapter suddenly turns off . the battery charging light in the laptop is not on.why?
Try another known good charger, also take the battery out to see if that makes any difference.
The socket for your laptop sounds to be worn out, this happens often, there are many cheap charger port replacement services out there.
Thank you. but actually i have tried another charger of the same type .it makes no difference .also i tried the same with battery removed itmaked no difference....