Sorry I'm late to the topic...
I had a similar issue when a Windows 10 update broke the drivers for my on-board video. I went from 3 monitors to one. After looking over the price of a new PC I went and got this:
ZOTAC GeForce GT 710 1GB DDR3 PCI-E2.0 DL-DVI VGA HDMI Passive Cooled Single Slot Low Profile Graphics Card (ZT-71301-20L)
It fit in the slots on my PC, it had W10 support, and it had three outputs - VGA, DVI and HDMI. I've got all three active once again. Installation was very simple. Took longer to download and update the drivers then to install.
Cost today is $47. Free prime shipping. It does say that it requires a larger power supply, but a bit of work with an on-line PC power supply calculator revealed mine had plenty of headroom.
73 de Chuck, WS1L--