so last night my monitor goes black, everything is plugged in and the hard drive is running. The power button?

First thing you need to do is determine if the problem is your computer or your monitor. An easy way to determine that is to hit some of the buttons on the front of your monitor and see if the on screen menu comes up and is displayed correctly. If it is displaying correctly then the problem is your computer, it is not coming up at all then the problem is your monitor.

If the problem is your monitor then you pretty much have to buy a new one since repairing them is not something most people should ever try.

If it is the computer then the first thing is to double check the connection cable running from the computer to the monitor and make sure it is not loose. I am also assuming you already restarted your computer by now and the problem did not go away but if not then do that and see what happens.

If the problem is still there then it is most likely a flaw in your graphics card. I have seen fried out graphics cards a lot in my own computer as well as ones I repair. I recommend you take your computer to a professional to get it looked at once you get this far since it is not easy to figure out exactly what the problem is.

Good luck.