I have a Windows 10 pro deskop which has a main monitor connected via DVI on the built in graphics card. This card also has a VGA output to a VGA splitter, which has a VGA out for a second monitor and also 4 cat5 to VGA outputs. Off these outputs I am running 2 different projectors. My main projector works without a problem, but the 2nd one can't find the source. I've connected this projector directly onto the VGA output from the graphics card and this works fine., I've tried a 3rd projector and this also works ok. I've tried the same setup with a windows 7 laptop and the setup works ok. All cables have been replaced. Any ideas would be much appreciated.