1 monitor stopped be detected

[FlightsimTed]

My PC is dual boot - Windows 7 32 or 64 bit. I have 6 Dell monitors connected to my PC. I usually boot into win 7 32 bit where all 6 monitors work. Today I booted into Win 7 64 bit and one of the monitors does not show the green power light just orange. The other five are OK. If I restart and boot into win 7 32 all is well again and the monitor with the orange light in win 7 64 bit goes green. In win 7 64 bit there only shows 5 monitors. Any idea what might be wrong? I assume that it is a software problem.

 

[file3456]

I would start to investigate settings in your video control panel. What kind of GPU do you have? How are these six monitors even connected?

 

[FlightsimTed]

I have 2 x Radeon HD7700 + GTX 1070Ti
3 monitors (DELL E190S) are connected to the GTX 1070Ti via Startech 3 way splitter DP port on the GTX in – 3 x DP out to VGA monitors.
1 monitor (DELL P190S) is connected to the GTX via [FONT=&quot]dual-link DVI port to dual-link DVI port on the monitor[/FONT][FONT=&quot][/FONT]

1 each (DELL P190S) are connected to the HD7700's dual-link DVI port to the dual-link DVI port on the monitors. It is one of these monitors that is not working in the win 7 64 bit. It does work in the win 7 32 bit with no changes in any lead or other connections.

This setup has worked flawlessly for at least 2 years.

- - - Updated - - -

Hello F22 Simpilot
Thank you for helping me.
here are some screen shots
The image Win 7 32 and 64 bit.jpg is identical on both systems
The image windows 7 32 bit screen resolution.jpg Shows all 6 monitors detected and OK
The image windows 7 64 bit screen resolution.jpg shows only 5 monitors
The image windows 7 64 bit screen resolution press detect.jpg after pressing the detect button. clicking the No display detected drop down box only shows Try in VGA mode. This too does not work.

 

[file3456]

I have a felling you need to use the AMD GPU driver control panel for the configuration of those connected monitors and the Nvidea control panel for the configuration of its connected monitors.

Mixing two different brands of GPUs is not a good idea...

 

[FlightsimTed]

I too are believing that it is something with the Radeon HD7700 graphics card but this system has worked setup has worked flawlessly for at least 2 years. I will look in to this. Thank you again

 

[file3456]

Well, it's kinda like plugging a hole on a steam pipe with bubble gum. At first it may work for awhile, but eventually it won't....

 

[FlightsimTed]

I have just completely uninstalled the 2 HD7700 cards and reinstalled them with the drivers DVD that came with them. It all works again. The drivers were not the drivers they have now. The windows system did not recognise the monitor so it did not show on the ADM control panel. With the windows 7 32 bit system it uses the same graphics system and has been running for over 5 years. Something updated the HD 7700 cards driver.
Thank you for your help