I think it's a windows problem... I did a restore back to about 10 days ago... everything works fine now & I have turned off automatic windows updates

I have double checked that Win 10 is uptodate
& have reinstalled the mostb recent video drivers for the geforce GT 740

My set up was working fine & then it suddenly stopped working
I am running Win 10 on my desktop with a DVI cable to my monitor & an HDMI cable to a Kramer switch box which then goes to my projector...