Latitude won't turn on

Always unplug the charger and remove battery before removing or installing any component inside the laptop. Now go to the teardown page:

Dell Latitude E7250

*Remove battery *Press power button to charge any power in system *Remove SSD *Remove RAM *CD drive

Plug in charger and press power button. Do any lights come on, fans spin?

If yes unplug charger then install one RAM and try again. Does anything happen, anything on the screen, does it try to boot-up and can you get into the BIOS? If yes then reinstall hard drive. Does it boot-up? If yes all is good. Now (not forgetting to unplug charger) reinstall the battery without charger. Does it work? If no replace battery.

If the answer when you reinstalled the RAM was no nothing happened then disconnect (again no battery or charger connected and discharge by pressing power button) the CMOS battery, teardown shows how to do this. Reconnect and try again with RAM and charger plugged in. Anything? If yes then reassmble other components one at a time.

What you are doing is just trying to eliminate the cause of the initial problem. A bad battery, RAM, hard drive or CD drive could kill the whole system by a short circuit. Resetting the CMOS by unplugging its battery could fix corruption. Also a dead or under voltage CMOS battery could cause problems.

Let up know how it goes.