Computer monitor wont stay on?

My dell computer monitor turns on for about 3 seconds before turning black. when it turns off i can press the power button on the monitor off and on and itll work again for 3 seconds again. what could be wrong with my monitor? and how can i fix this?
Update: i tried the monitor on another computer and the same problem happened, the picture shows then it turns off.
Update 2: i tried the monitor on another computer and the same problem happened, the picture shows then it turns off, is there any way to fix the monitor?
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