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Windows 7: Windows 7 Won't Detect My Primary Monitor

19 Nov 2009   #21

Windows 7

I just ran into this problem as I tried to install Windows 7 on a Alienware Area 51 m5500 with a NVIDIA 6600. Once the NVIDIA driver loads for the first time the Device Manager only recognizes the external display. As meintioned in post #18 closing and opening the lid somehow notifies Device Manager that the LCD of the laptop is alive and well. Once the Laptop LCD is detected it can be configured as the primary monitor with the desired resolutuion. The issue is that this setting is lost every time one reboots. This is not WAD... there is a bug somewhere with Device Manager as it tries to work with the NVIDIA drivers. During the initial boot up process the laptop displays the "Starting Windows" message in the laptop LCD, but once the NVIDIA driver loads the Laptop LCD goes black. One can either connect an external display to see the Windows 7 logon screen or close the lid and re-open it so that Device Manager senses the LCD.

Someone in MS please file a bug.

My System SpecsSystem Spec
21 Nov 2009   #22

Windows XP Pro SP3 & Windows 7 Ultimate (Dualboot)
possible fix


i came accross this thread in search of an answer to my same problem. oddly, i was having the same problem but with a CRT, a Gateway VX930. i tried contacting Gateway about it but they couldnt even bring up the model i gave them from my seriel number. then they wouldnt help me because i dont have it hooked to a Gateway computer. so they were no help. however, as i read this thread i seen you talking about it being a driver issue, so i started trying some things and WALA! i got a solution to my problem, and hopefully it will help you too.

first i must explain the problem. i hooked up the monitor and it worked great in Windows XP. so i rebooted and went into 7 (i have dualboot). well, i seen the Windows 7 loading screen, but as soon as it was about to hit the Logging On screen, my monitor went to standby. booting into safemode, i could see the monitor wasnt detected in Device Manager, but it was named Default Monitor in Monitor tab of Advanced settings. i could not however change the properties for the monitor. nothing up to this point helped me.

Here is what i did:

1. Start your computer and before the loading screen press F8 (like you going to SafeMode)

2. Choose Enable low-resolution video (640 x 480)

3. Press Enter

At this point you should have booted up successfuly with your problem monitor working fine (in 640 x 480) Go ahead and see if Windows will let you select any other resolutions now. If it does, restart your computer and boot into Normal Mode and see if your monitor stays on and at the res you chose. If not, this was the case for me, reboot back into low-resolution mode (Step 2), and continue to Step 4.

4. Once loaded back into low-res mode at 640x480, goto the Start Menu and type in "regedit"


6. Now under this DISPLAY key, there should be a key with a name that relates to you monitor (mine was \GWY232D\ for my Gateway VX930). Under this you should see another key that has a long string of numbers and letters (mine was \5&3a3a8fd1&2&UID33554688, yours may be different)

7. Under the key with the sting of numbers and letters, see if you have a string called Device Paramaters, and under that, MODES. If you dont have Device Paramaters\MODES, manually create them (right-click on the string of numbers and letters, New -> Key, then right click on Device Paramaters, New -> Key)

8. Under MODES, you may see a key that has your monitor's native res (ie. for my 19", the key was 1600,1200). There wont be anything in it, but dont worry about it.

9. Right-click on MODES now and make a new key for each of the resolutions you want your monitor to have (i made 800,600 1024,768 and 1280,1024, BE SURE to make a key for the resolution you plan to use!)
Make sure you name them like "1024,768" "1280,1024" etc. but without quotes ofcourse.

It should now look like this

-Device Paramaters

Now i dont know if this is required, but i did it just to be sure. Click each of the keys, and in the right panel, notice the key labeled (Default) and next to it it says (value not set). Double click it and then just press enter. You should see the (value not set) go away and it will just be blank. Do this for each and then you can close out of Registry Editor.

10. Right-click desktop and go to Resolution

11. Pick the resolution you want and click apply. It should successfully apply it now.

12. Reboot the computer into Normal Mode and if all went well, you should have your monitor working properly at the resolution you wanted.

Thats it, i did all that and it fixed my problem. Hope it works for you too! Reply and let me know if it does..
My System SpecsSystem Spec
22 Aug 2011   #23

Windows 7 Home Premium 64bit

My laptop Windows 7 symptoms from plugging in external monitor were:

- Laptop LCD panel turns off
- no laptop LCD monitor in device manager

my solution was:

1. start computer fresh without external monitor
2. windows key + P
3. select extend monitor
4. plug in external monitor

go figure...
My System SpecsSystem Spec


 Windows 7 Won't Detect My Primary Monitor

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