The coin battery in your top box has died.
You will need an old computer keyboard with the small purple plug and a cr2032 coin battery.
Carefully open the top box and replace the battery on the computer motherboard inside.
Then plug in the keyboard. The plug is on the side of the top box. USB keyboard will not work it must be the old style with the small purple din plug.
Start the machine and keep pressing the delete key until the computer bios screen comes up.
Tab over to where it says "load optimized defaults " and hit enter. Save optimized defaults and then go to save and exit. Press yes to save. Machine should then reboot without errors. Turn off unplug keyboard and you should be good to go.
Rich