When Plug and Play goes wrong
QUESTION I have paired a 19in Hanns-G monitor with a Windows XP laptop over VGA for several years now, running at 1400x900. I recently turned on my computer to find the screen resolution had changed and I could no longer select a widescreen aspect ratio. I've tried a factory reset, changing the VGA cable, refreshing the graphics and monitor drivers, altering the refresh rate, uninstalling and reinstalling the drivers in Safe mode, and rolling back the machine using System Restore. I've even specified a 1400x900 default resolution in the Registry, and tried the monitor with both Vista and Windows 7 computers. Nothing works! Beatnik
HELPROOM ANSWER Plug and Play monitors announce their resolution capabilities to your connected computer by means of a protocol called DCC. If, for some reason, this information isn't reaching your PC, then the computer will make some assumptions about the monitor's capabilities.
These assumptions can often be wrong, frequently resulting in the type of problem you describe. Since the same thing is happening on multiple PCs, it's likely that the problem lies with either the monitor or its connecting cable.
The first thing to check is whether the monitor has an option in its menu to turn off the DCC function. It's not universally supported, but some displays have this function lurking deep within the onscreen menu system. When DCC is disabled, the display won't function as a Plug and Play device and your PC should be free to select any video resolution.
If Windows is using the generic Plug and Play monitor driver, it will restrict you to selecting only the resolutions explicitly enabled by the monitor. If the monitor is providing the wrong information, you can often override it by selecting a monitor driver that explicitly supports the resolution you require.
If neither of these options fix your issue, you may be able to create a custom resolution using your graphics card driver software. Alternatively, you can try a utility such as PowerStrip 3.90, which will provide comprehensive control over custom resolutions for a variety of different graphics cards. Using this utility you should be able to force your system to output the required resolution, regardless of what the monitor is telling your PC.
Another way to disable DCC is to physically remove pin 12 from your VGA cable. We'd suggest finding an old, spare cable if you want to try this method.
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