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I have setup a dualscreen setup for my notebook with an ATI video card (ATI mobility radeon hd 5470) using Catalyst Control Center.

The monitor extends the desktop of the notebook's screen. This works great.

I am running on windows 7 and have set it up to not do anything when I close my laptop's lid (case) other than dim the notebook's display.

However, when I do close the lid (notebook's display), the second monitor suddenly changes and I believe it starts behaving as the primary monitor.. I do not want this to happen.

So, how do I setup my dualscreen setup so that it won't set the secondary monitor as the primary one when I close my laptop's lid?

UPDATE: this video shows exactly what my problem is: http://www.youtube.com/watch?v=Q1ygNHbqI2g

Hennes
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Tom
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2 Answers2

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As Shinrai said, it's probably the notebook's hardware shutting off the monitor (and detaching it) when the lid closes, regardless of what the OS is set to.

Check the notebook's BIOS settings and see if there's any options you can control about the monitor turning off on lid-close in there.

If not, then you're pretty much done-for if you need the internal to be the primary, because if you don't have a primary, you can't have a secondary; so the secondary monitor will always automatically become the primary when the primary is disconnected/detached (via hardware).

Add: This is a guess:

Perhaps try setting the notebook's monitor driver to 'Generic Plug and Play Monitor' or alike. Perhaps that will break the ability for Windows to know it's 'attached' state.

Ƭᴇcʜιᴇ007
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Solution from prevent monitor switching when closing laptop lid :

Go into registry and create a new DWORD called "LidAlwaysOpen" set value to "1" in
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Video\"YourDisplayGUID"\0000\

Some user have been reported this will work only for first lid closure, but not for subsequent ones.

The thread annoying extended desktop in windows 7 offers another possible solution :

  1. Open device manager
  2. In "System devices" find "ACPI lid"
  3. Open "ACPI lid" properties, and go to "Driver" tab.
  4. Select "Update driver"
  5. Choose "Browse my computer for driver software" and "Let me pick.." uncheck "Show compatible hardware"
  6. And now...in "Manufacturer" select "(Standard system devices)" and model: "Volume manager" (yes, "Volume manager")
  7. Next, next, restart the system and it works!
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harrymc
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