I've a HP PC and 2 Dell monitors with VGA out. I got 2 VGA to HDMI cables and also one HDMI splitter (2 in and 1 out to my computer). When I turn the monitors on - they both mirror each other and my PC one sees 2 screens (PC and one monitor. I then unhooked one monitor and paired it with a separate HDMI to USB into my computer. Now that monitor doesn't show up at all and my PC still only shows 2 screens (PC & one monitor). I do know my PC can "see" 3 screens as I had 2 small portable monitors working but they were too small for daily tasks. Help, please.