Problem with Dell 24" monitor turning on.

[Airbrushkid]

I have 3 - Dell 24" E248WFP monitors. One has been acting up for the past year. When I turn it on it just sits there. Power button blinks green. That's it. I do know when the room is cold it happens more often. When room finally heats up it will start.
I leave the air conditioner on over night. So in the morning when I get home, I have to turn the air conditioner off for a while till the monitor starts. But right it's got worst. It takes a longer time to start.

Has anyone ever heard of something this problem with a monitor?