you asked us what can you do about this shocking if you had tried before you did understand that this shocking affect happening when your laptop is plugged in and i think if you unplug the adapter this wouldn,t happen
but you can,t use your laptop by battery cause it,s annoying that you should always recharge your laptop and use it and beside that your battery can,t keep electricity well ( because of its age) so here is my solution
try to wear slippers i am not mocking you yeah it can stop it , your body is a contact between your laptop and earth you can cut this contact by wearing a Nonconductor material like slippers
but in general i suggest you to buy an original dell adapter , well if your adapter is original already ,try another adapter