monitor or video card broken?

My fiance hooked up my Dell desktop monitor to his laptop to do some work. I came home later, turned on my computer and saw some message on the monitor that reminded me that he had disconnected it. Without powering anything down I plugged the blue and white plugs back into my CPU. I then heard the same quiet "poof" that I normally hear from the speakers (attached to the monitor) when I power down the computer. The monitor was dark and I pressed its power button which was glowing with the orange "power save" light. I could not get the monitor to turn on. I restarted the computer to see if that would fix my problem but it did not. Did I blow out the monitor or maybe the video card?

 

It doesn't sound like your monitor broke down. Could you please check again if the D15-SUB cable is connected correctly to both your monitor and your graphics card? Also, you could try to unplug the monitor and your PSU, then plug them again and start the computer.

This has happened to me many, many times, so that's why I recommend the above. If nothing works, we will continue from here.