I have an AOC monitor at work. While on annual leave, I believe a colleague in a panic over a suspicious email may have pulled out the power cord to the monitor when pulling out cables of the whole PC system. Since then, when you plug the monitor in, it flashes up AOC then powers off, then powers up again within 1 second and displays AOC and powers off again. This just keeps repeating. I'm assuming maybe some damage has been caused to the power input but thought worth trying a reset.

Computers & Internet - AOC