What registry key or windows file determines where monitors are placed in a multi monitor environment?

For anyone that is looking for the key in Windows 7 it is in one of the folders in:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration\

Look for Position.cx and Position.cy in each of the subfolders; you have to edit the hex string.

Binary / decimal / hexadecimal converter:

http://www.mathsisfun.com/binary-decimal-hexadecimal-converter.html

Check out the various keys and folders in

HKEY_CURRENT_CONFIG\System\CurrentControlSet\Control\Video

Specifically in the innermost MonXXXXXXX sub-folders should be Attach.RelativeX and Attach.RelativeY values which are the monitors' location in relation to pixel 0,0.

Strangely when I check a Windows 7 machine here with two monitors, it doesn't seem to show the second monitor. But my XP machine shows all three of mine, so your mileage may vary.

If nothing else it's a place to start!

I wish I knew why this worked but I know it does:

To get the monitor to go UP (because negatives aren't allowed by the registry), you have to use values for attach.relativeY like this: 4294967040

Thanks to this forum for helping figure out that part - http://www.ureader.com/msg/164488.aspx

If you change the last 4 digits of that number down, the monitor goes down and vice-versa. This will also work for attach.relativeX. A little tweaking and my setup was back to normal.

Who needs functional drivers pshh