Dual Monitors - Only One Works at a Time

Discussion in 'Windows 7 Help and Support' started by SpiderKnives, Aug 3, 2010.

  1. SpiderKnives

    SpiderKnives New Member

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    Hello,
    I've recently switched from Windows Vista to Windows 7 x64. I use the word switched instead of upgraded because I formatted my old drive instead of installing over Vista.

    I have been using two screens for forever now, both LG Flatron L1750HQ, both are digital and have served me well. My graphics card is an NVIDIA GeForce 8800 GTS, which has two digital outputs. I have the latest NVIDIA drivers, and I have the drivers for my screens (though they are old, June 2007, and I can't find any newer ones... which might imply an EDID problem? Dunno). I have also run every Windows 7 update known to man.

    To describe the problem: only one of them ever works at a time (which implies the screens themselves are okay), and both outputs work as well. To top that, Win 7 does recognize I have a dual display, but one is always in digital power-saving mode (no signal, I guess).

    When my computer boots up, the left screen shows the boot process, while the right one has no signal. When Win 7 boots, its the other way around.

    In the NVIDIA -and- the Win 7 control panels both screens are visible, shown side by side, and set up properly with and without the screens' driver, but that does nothing to solve the problem.

    I've also examined my BIOS, but I doubt its anything to do with that since I haven't touched my BIOS in ages and it worked just fine on Vista. I'd wager that if I go ahead and install Kubuntu on this machine, I'll get my dual screens back, but I don't want Kubuntu.

    Thanks in advance for any assist :)
     
  2. zvit

    zvit Honorable Member

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    You should not need the screen drivers for dual monitors to work.
    Make sure you actually have the latest drivers and try again. (Choose the x64)
    NVIDIA DRIVERS 258.96 WHQL

    You can try to use this to set up your monitors:
    Realtime Soft UltraMon

    Do you have both VGA and DVI connected from your 8800? If so, remove the VGA connection and see if the issue is resolved.
     
  3. TorrentG

    TorrentG Banned

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    Right click the desktop. Choose Screen Resolution. Make sure the orientation is set to landscape and that multiple displays is set to extend. Also that both monitors are enabled.
     
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  4. Saltgrass

    Saltgrass Excellent Member
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    When I did my test on 2 monitors, the primary monitor always showed the boot and login pages while the secondary monitor was blank. After login, the secondary monitor displayed as it should. I had 2 LG monitors of different sizes and resolutions running off a 480 GTX.

    The fact they are older may or may not be related, but I assume you are running both off a DVI connection...and have both monitors set for Digital inputs.

    This is just total speculation, but I was wondering if 2 drivers would be needed for the 2 monitors. Since they are the same, could it possibly be that only one driver can be used at a time? Have you loaded the drivers for each monitor and they both show up as the correct model number in Windows? Also on my newer LG monitor, I have drivers for HDMI and DVI and VGA inputs I can load from the DVD.
     
    #4 Saltgrass, Aug 3, 2010
    Last edited: Aug 3, 2010
  5. SpiderKnives

    SpiderKnives New Member

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    First of all, thanks for the replies guys.

    Saltgrass - I've tried it without drivers (that is, generic PnP), then I've installed drivers for the one not working, and, when that didn't help, I updated the other one as well. It upped my refresh rate, but not much more. Yes, both are DVI, and both drivers are digital, and have the proper driver name (L1750HQ(Digital) is how it shows). Yes, both monitors needed updating manually and separately.

    Also, what you're describing, where one screen boots and the other shows Win 7 is exactly what's happening to me.

    TorrentG - Yep, I've fooled around hoping anything would get a rise out of the dead monitor, to no avail, and I've also returned it to the settings you've mentioned.

    zvit - confirmed latest drivers. As for UltraMon, I've tried it now and while it has some neat features, unfortunately it behaves the same way Windows 7 does - as if the monitor is plugged in, working, and everything is peachy. Trying to change the settings doesn't do much either. How upsetting.

    Interestingly enough, if I switch between primary and secondary the same screen that's working becomes the secondary while the primary is still dead. So it's nothing to do with which is what, and more to do with one output working and the other one isn't. Huh.

    Thanks again for the reply, btw :)

    Help!!
     
  6. Saltgrass

    Saltgrass Excellent Member
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    You misunderstand. After I log into Windows, the other one comes on so both screens work as they should. If your primary screen goes out after log in, perhaps it is not set for a digital input or the refresh rate/resolution needs to be changed.

    It still could be the video card acting up or not completely compatible with Win 7.

    If you disconnect the secondary monitor, what happens to the primary monitor during normal operation?
     
  7. bassfisher6522

    bassfisher6522 Essential Member

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    First, check your refresh rates of both monitors. I have to monitors, two different brands and both run at different refresh rates. Second, you could try uninstalling your GPU, unplug second monitor, boot up with on board graphics to confirm monitor is working, shut down and reinstall GPU and boot up and load GPU driver, then reattach second monitor. If you haven't all ready tried this that is.
     
  8. SpiderKnives

    SpiderKnives New Member

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    As for the refresh rates, both screens are identical and both have exactly the same settings anywhere down to the less tidbit.

    Thanks bassfisher, will try this tomorrow. Updates asap ;)
     
  9. SpiderKnives

    SpiderKnives New Member

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    Okay, tried what bassfisher said and now its getting weird - when I remove the other screen, no amount of tinkering will acknowledge that it isn't plugged in. Maybe there's a different problem, one where the computer insists that it always has two screens plugged in even when it doesn't, and that was masked by me trying to plug two screens at the same time to begin with? Ugh. Still though, nothing helped. Uninstalled, unplugged, confirmed working, reinstalled, replugged, still Digital Power Saving Mode on the second screen. :(
     
  10. bassfisher6522

    bassfisher6522 Essential Member

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    Is there an option button on the monitor itself to reset to default settings. Did you try changing the second monitors refresh rate to some other than what the first monitor is? My primary is at 60 htz and secondary monitor is set at 75 htz.
     
  11. SpiderKnives

    SpiderKnives New Member

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    Thanks for sticking with me, bassfisher. Unfortunately Windows doesn't let me change the refresh rate on either monitor, even if I check the box for showing unsupported rates. Maybe I should get something to bypass this? RefreshLock? Dunno.

    Anyway, I tried changing my drivers from the Digital ones to analog, no dice, still the same, still no other refresh rates to choose from and nothing has changed.
     
  12. bassfisher6522

    bassfisher6522 Essential Member

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    Well, I'm scratching my head now as what to do next? The only thing really comes to mind, is it's a hardware issue with the GPU, that's not playing nice with your version of 7. There could be some bad/defective parts or ram on the card. The only other option I can come up with now is to do a "part change". If you can get your hands on another GPU of same make/model and install it and see what happens or get one that has the same features as yours does from a friend and check it out for the same issues your having. Other than that I'm out of options and maybe some one else might jump in.
     
  13. zvit

    zvit Honorable Member

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    I also can't figure it out. Since it worked with Vista, I doubt it's a hardware problem. It's got either something to so with the drivers between the Nvidia card and Window 7, or the settings in the Nvidia card are wrong. Yes, I know, you tried everything so I don't know what to say.

    Only thing you can do besides going back to Visa is try opening a support card with Microsoft and Nvidia:
    Microsoft: Microsoft Support
    Nvidia: Support

    Maybe by some miracle, one of them will answer you.
     
  14. TorrentG

    TorrentG Banned

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    In safe mode, use Driver Sweeper from Guru3d.com to clear out all NVIDIA files and settings from the machine. If you have an NVIDIA chipset, be careful not to remove these files and settings while using.

    Boot to normal mode and install the latest driver for your card from NVIDIA.com and hope for the best.
     
  15. SpiderKnives

    SpiderKnives New Member

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    Thanks TorrentG, but no progress. Tried what you said to the letter and nada.

    I think I can isolate a symptom, though - what if it thinks there's a monitor plugged into the secondary output? I dunno how to put it into words exactly but it seems like after I tried what you said it claimed I have two screens despite one not being connected when I wiped the drivers.
     
  16. TorrentG

    TorrentG Banned

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    I didn't re-read everything so if I'm being redundant or saying something not applicable, please forgive that...but....

    Enter the bios and make sure the onboard vga is disabled. Also make sure both monitors are plugged into the video card. No video connections should be to the motherboard itself.

    I'm fairly certain these aren't your problems, but I had to mention anyhow just in case.
     
  17. word54

    word54 New Member

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    I know that this response is 2 years too late, but I figured I'd post it since I only recently found the thread, it might prove useful to someone dealing with this issue.

    So I've had this exact same problem, with BIOS splash screen showing on one monitor, then Windows 7 login on the other. After a little bit [I just reinstalled Windows to clear some stuff up], the login screen never showed up... even after the "Starting Windows" load up screen. The monitor that showed BIOS splash was black with my cursor and the monitor that usually shows the login screen was inactive. After trying a litany of troubleshooting procedures, I just unplugged 1 monitor and ran Windows normally. I then plugged in the second monitor and the computer detected it, but showed nothing on the screen. Nothing I could do would get the second monitor to get a feed. My friend, who was helping me troubleshoot, just pushed a button on the dysfunctional monitor [the menu/exit button in this case] and it "woke up" with the desktop working just the way I wanted it to!
     
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  18. nikpapag

    nikpapag New Member

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    SpiderKnives,
    I have the exact same problem. Did you ever get your 'Dual Monitors - Only One Works at a Time' problem resolved 2 years ago?

    I just noticed that you DID reinstall Windows 7 to make it work. Was it a GeForce 8400 GS with a DMS-59 output?
     
    #18 nikpapag, Sep 24, 2012
    Last edited: Sep 26, 2012
  19. bd3D

    bd3D Well-Known Member

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    when u press the key combination "WinKey+P" and select "Expand" does that help, nikpapag?
     
  20. nikpapag

    nikpapag New Member

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    Thank you bd3D. That's a good tip I hadn't known about. But, no it makes no change even though the system thinks dual monitor is working.

    I also tried the other tip above 'pushed a button on the dysfunctional monitor [the menu/exit button in this case] and it "woke up" with the desktop working'. It did wake up monitor 1, but says,
    1: Analog Input in Power Save Mode
    Press Any Key on Keyboard or Move Mouse
     
    #20 nikpapag, Sep 25, 2012
    Last edited: Sep 25, 2012

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