Latitude 5440 green red blue white issue

Dell Latitude 5440

Model Dell Existing warranty

1-Reason for Entry equipment received power failure and absence of signal on the screen

2-Observed symptoms

-Laptop partially turns on, the keyboard and power button light illuminates

-There is no video signal on the internal screen or through the external HTMI connected to other equipment

-The fans turn on and it makes noise

-When connecting the charger, the device has changing colored lights (green, red, blue, white, black)

-no bios beeps are heard -after a while the computer turns off by itself

3-Tests carried out -basic ignition with model charger

-peripherals disconnected

-HDMI connected but does not give a video signal (No disassembly has been carried out)

i need help please,