What could cause the computer’s display to go darker suddenly


My monitors lost their brightness without warning or reason. I left my computer alone for a couple hours, and when I came back my monitors were so dark I could barely see anything.

It looks as if the brightness setting on my monitors was turned all the way down, except that the brightness is cranked up as far as it can go – the way I always have it. Furthermore, my monitors are both having the same problem simultaneously, which makes it seem like it's not a problem with the monitors themselves.

My computer consists of the following:

  • Motherboard: BioStar M7NCG 400
  • CPU: AMD Athlon XP 2200+ 1.8GHz
  • RAM: 2.5GB
  • HDD: Three drives – 40GB, 120GB, and 160GB
  • Optical: Single DVDRW
  • Removable: 1.44MB Floppy
  • Video Card: NVidia GeForce 4 TI 4200, DirectX 8 Compatible
  • Monitors: Two Gateway VX900 19" CRTs accepting VGA output

One of my monitors is plugged directly into the VGA port on my video card. The other one is plugged into the DVI port on my video card, with a DVI-VGA adapter in-between. I should also mention that my video card may be eight years old, but it was made with one of the largest and most reliable video processing chips available at the time. It still runs many current video games without problems, and I would have to spend several hundred dollars to replace it with something comparable. This is why I'm trying to keep it alive as long as possible. I bought it new in '00 or '01, and I've never had the slightest problem with it. I've taken excellent care of it, keeping it cool and dust-free. So it's difficult for me to point at a hardware malfunction as the culprit.

I can see basic aplications alright, as long as they have a lot of bright colors in them. But this is still the most frustrating thing I have ever seen. It's driving me nuts.

Does anyone know what could possibly cause this type of occurrence?

My only theory is that maybe the drivers have caused an error and kicked down the gamma or something. Can anyone verify or deny that this is possible? And where in the NVidia application(s) could I find the gamma settings? I have tried restarting my computer to no avail.

Best Answer

If ChrisF's suggestion didn't help, there are a couple other things you can try: Try pulling out and reseating your video card and try replacing the connection cables between the card and the monitors and also the cables from your power supply to your video card if it has one.

Failing that, you can also try uninstalling and reinstalling any drivers for your video card and monitors. I have seen a situation before where that helped.

If none of that helps, my next guess would be video card is failing.

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