Dead as a doornail

Meaning

Used to describe something that is definitively broken, finished, or lacking any sign of life. It emphasizes that there is zero chance of recovery.

Definitive, bleak

Used in a sentence

• The computer screen went black and is dead as a doornail.
• After three days without water, the plant is dead as a doornail.
• My old car is dead as a doornail and not worth fixing.