I have a Dell Optiplex 780 computer (using a AMD Radeon 3450 if that helps), which I connect to my monitor with a DMS-59 splitter, to split it into 2 VGA cables.
When booting into BIOS, both monitors display the BIOS screen, and even the windows (7) loading screen is shown on both monitors, however, when windows actually loads up, one of my screens does not show an image, just a black screen.
Both screens are usable when used as just a single screen, it is just when trying to set up dual screen that I have run into this issue.
Can anybody help me work out how to make my second screen usable in Windows?
Thank you very much
Best Answer
I'm assuming you've already tried going into AMD Catalyst Control Center and (separately) Windows' own screen properties (right click the desktop) and trying to enable both monitors?
If this is a NEW problem (you've gotten this to work before with the exact same hardware)
Try updating your drivers. Note that you are using an End-of-Life unsupported video card which is not receiving regular driver updates from AMD anymore, so if it is a driver problem, there is very little hope that a fix will ever arrive.
Try reinstalling Windows, or at least boot up a Live CD/DVD of Ubuntu or Fedora and see if that can detect and initialize both monitors.
If you've never gotten dual monitor to work before
It could be that the total resolution of both your monitors (add up the vertical and horizontal) may be greater than the supported framebuffer size of your GPU. Considering how ancient your GPU is, this isn't very hard to imagine being the case. I was only able to find one anecdotal site after many minutes of googling showing that the maximum resolution is possibly 2560x1600. If you're trying to connect two 1080p displays (1920x1080), then 1920*2 = 3840 and 1080 * 2 = 2160, both of which are greater than the maximum respective WxH components of 2560 and 1600.
It could be that the driver support is not there. Again, trying to update to the latest supported driver or running Ubuntu to see if it also breaks there might provide more info.
It seems like you're not the only one with this question, either.
The only real solution I can think of is to use an actually modern GPU.