Xbox starts and shuts off automatically within a few seconds (read description)

I haven't played on my xbox since a few months and yesterday i tried to turn it on, it immediately shut off offi left it plugged in but it kept on turning on and off automatically.

I have tried changing the power suplly and its still doing the same

I have plugged it directly to wall but no go

I have tried to turn it on by attaching the controller with usb but the controller wont connect

Also you can hear the eject beep but the button is not pressed at all

Also i tried starting it by removing the front panel but still it keeps shutting off

Any fix is possible? What could be damaged?