Arduinno heatinng up and shutting down in 15 seconds.

Hello community,

I am new in Arduino programming. My Arduino Uno is shutting down in 15 seconds right after connecting via USB.

Arduino: 1.8.10 (Linux), Board: "Arduino/Genuino Uno"

Sketch uses 3868 bytes (11%) of program storage space. Maximum is 32256 bytes.
Global variables use 234 bytes (11%) of dynamic memory, leaving 1814 bytes for local variables. Maximum is 2048 bytes.
/home/oem/Downloads/arduino-1.8.10/hardware/tools/avr/bin/avrdude -C/home/oem/Downloads/arduino-1.8.10/hardware/tools/avr/etc/avrdude.conf -v -patmega328p -carduino -P/dev/ttyACM0 -b115200 -D -Uflash:w:/tmp/arduino_build_102787/sketch_dec13a.ino.hex:i

avrdude: Version 6.3-20190619
Copyright (c) 2000-2005 Brian Dean,
Copyright (c) 2007-2014 Joerg Wunsch

System wide configuration file is "/home/oem/Downloads/arduino-1.8.10/hardware/tools/avr/etc/avrdude.conf"
User configuration file is "/home/oem/.avrduderc"
User configuration file does not exist or is not a regular file, skipping

Using Port : /dev/ttyACM0
Using Programmer : arduino
Overriding Baud Rate : 115200
avrdude: ser_open(): can't open device "/dev/ttyACM0": No such file or directory

avrdude done. Thank you.

Problem uploading to board. See for suggestions.

the green led slowly fades away. I tried using reset button, that didn't help either. USB is working and is totally fine for mass storage devices.
the black and gold thing 5081 or 1805 written on it, heats up at untouchable temperature.
board : arduino genuino uno
programmer : avirisp mk2
The question is the board dead ?