LCD Monitor turned very dark?

What has happened is that the inverter has died. In principal you can replace this, and it is relatively inexpensive (I have to do this a lot with laptop screens).

If you take it to someone to get it repaired, make sure they don't charge you to replace the screen as the screen itself is fine - it is only the inverter that needs replacing (and it is not very expensive).

If you do this yourself, you will need to open up the monitor to find out the make and model of the screen, and order the appropriate inverter for it. There will be a thin, rectangular PCB which attaches directly to the screen, often covered in a plastic cover. This is the part you will be replacing.

UPDATE: Liv, when the inverter goes, the screen does not light up at all - it can not, because the inverter is what powers the back light. When the screen lights up and then darkens it is because of either a loose connection in the wires of the inverter, or the signal cable.

It is extremely rare for a back light to fail - in fact in fast approaching 20 years in the profession I have never once had to replace a back light, only ever the inverter. Which is a good thing, because replacing the back light means you have to actually take the physical screen apart.

Lcd Monitor Dim

This sounds like a backlight failure or inverter board failure. The backlight is the bulb that lights up your LCD monitor screen while the inverter is the what powers it.

You know it's an inverter problem when your monitor starts normally and displays the startup/desktop screen for a while. Then it suddenly goes off, leaving a blank (black) screen or a very dim display.

Alternatively, if your LCD monitor stays black right from the start, then it's a backlight bulb failure. Your screen is fine, you just need to replace the backlight or the inverter.

Check to see if the monitor's cable is in the pc properly if not I would say its a monitor problem

The cable could have a controversy, yet extra advantageous than probable you're having different matters. My suggestion is to first plug yet another visual demonstrate unit in and notice if it nevertheless does that. If it does, then the situation is interior the snap shots card. If it does not, then the situation would be with the visual demonstrate unit. I recommend the troubleshooting first, then replace the broken element.