In the Xbox settings video output to dvi converted now everything is black what now?

Hi

Earlier, I gambled on my Xbox and a friend said because I'm playing on monitor and I connected the monitor and the Xbox with an HDMI cable should I in the account settings but once in sound & video output said that I think it's time to switch to DVI I have done and zack the screen was black and remained black the sound I still hear but everything is black. What can I do now so I can switch back to HDMI because everything is now black?

I urgently need help

Connect a DVI cable

Yes the problem is Xbox has no DVI connection