Question Dell E5470 is not switching on; What to do?

[5omeone]

Hello tH-community,

my Dell E5470 is not starting and I have no idea what the problem could be.

• The charging cable is connected and lights up blue.
• When I press the power button, the power LED lights up briefly but switches off again immediately.
• The screen always remains black.
• The battery LED lights up white constantly when the power adapter is connected and goes out after a certain time.
• The notebook has not been used a longer time (roughly 2 years).

I initially thought that the battery was defect, but that doesn't seem to be the problem. I have installed a new battery, but the problem persists.

Does anyone have any idea what the problem could be?
Thank you very much and best regards