Heres the facts
The circuit board that receives the charging jack is seperate to the mother board on most Dells. It is a push together connection which relies on the integrity of the screws and their tightness to maintain a connection. With use or rough handling this connection may falter and need to be remade.
Sometimes it is the charger but rarely, sometimes it is the socket which you should resolder once you have the board out but 99% of the time it is this perilious little connection.
The Dell charger has a little pin in the middle of the jack (have a look in the centre)that interrogates this connection every time you plug it in. It is a little Eprom in the charger itself. The quality of this connection is key to whether the mother board will allow the charger to attempt to charge the battery. A poor connection leads to possible sparking and tthe accompanying RF is disasterousand could causes battery damage as well but mostly it's the danger of surging.
The ONLY solution is to pull the laptop apart, remove the mother board, clean both sides with a dry toothbrush or a contact cleaning spray and reassemble. Dells are very easy to work on, even a novice could probably do it, just make sure you take photos as you go to refer to if needed on reassembly.
So just to be sure - there is NO software, No downloadable fix or anything else that will solve this problem, it is a very simple hardware issue. If you are sending it to a Tech to fix, tell him/her about the Eprom etc and what needs to happen as most do not know.
The job takes about 30 - 40 mins and you should be charged accordingly - there is NO part replacement, unless the socket board has cracked due to rough hndling and needs to be replaced.
Good Luck with it all