Dell Latitude E 7240 does not start and no LED lights, what can I do?

My laptop does not start more and shows no reaction to plugging in the power supply (lamp on the power supply lights and secondly PSU was also tested) no led lights and no sound is heard. What else can I try?

Remove the battery, then connect the power adapter. Does he then stir?

No, then nothing.

That's a bad sign. Before you give it anywhere to repair:

Remove plate!
There's your data on it, not the ones that get deleted. You can also read the 2.5 "disk on a PC.

It's impossible to do anything by remote diagnostics. My idea was that maybe the battery has a defect and therefore a protective circuit prevents booting.