Pc works perfectly with HDMI, but I want to use dvi so when I change out the cables pc shows post and ASRock logo on screen but after that no signal, pc still on and fine.
Ah ok. In that case go into display settings in windows and detect displays, that should remove any reference to the second display you had connected. Then swap your cable and you should be good to go.
That happens quite often with Windoof.
Windoof is still seeing the monitor with HDMI is your only and main screen.
Because you do not have 2 monitors anymore, does your current monitor still have HDMI free? plug it there and your problem should b fixed.
Ah ok. In that case go into display settings in windows and detect displays, that should remove any reference to the second display you had connected. Then swap your cable and you should be good to go.