How do I turn the screen round?

How do I keep my HP w1907 LCD monitor from showing a black screen after changing resolutions?

• A black screen always shows whenever I change my monitor's resolution. It often happens in playing games like Soldier Front, where you always change resolution after each game. The only way to fix it, is to turn off the monitor and wait for few seconds then turn it on again. But sometimes when I turn it on, a black screen then appears and I have to turn off the monitor again and turn it back on. Which is really irritating when playing games. I always get killed on the first round because my screen is all black. It also happens when using Windows Photo Gallery's slide show function. After changing to 640x480 screen resolution, the screen often turns black. -- Windows Vista Home Basic HP w1907 19" widescreen LCD monitor (which came with the HP A6540D desktop package) NVIDIA 8400 GS video card 2.00 GB of RAM

• Answer:

  Could be a bad video card. First I would recommend updating your graphics drivers and any other hardware you may have. Try another monitor and see if it does the same thing, if not, probably your monitor.