I couldn't find the manual for your DVI version of the TV on this site. Here is a link to another. 

https://www.manualslib.com/manual/574238/Bang-And-Olufsen-Beovision-7.html?page=33#manual 

The link might open at the correct page, so follow the instructions there.  B&O TVs work slightly differently in that you cannot step through connected inputs. You have to set it up to be a button on the remote. So for example, if you set up your STB to be DTV or SAT on your menu, you need to press tha button on your remote to go to that input.

It would help if we knew the version of your remote. Can you list the second and third row of buttons below the screen. Mine says 

DTV - DVD - CD

V.MEM - RECORD - A.MEM

Also, what make us your STB? When you say it is loading, what do you see on screen?

Stoobie 

I've recently got a 7-32 Mk3 and had the same problem with a Apple TV (2015).

I did the following:

- Set the resolution to 720p on the ATV on a different TV

- Got a DVI-D Dual link instead of a DVI-D Single Link. Not sure if this fixed it but it worked immediatel after I changed it.

- Plugged in the ATV first and then starting the Beovision

Maybe this will help you.

This link might also help. 

/forum/general-discussion-and-questions/beovision-7-40-hdmi-to-dvi-adapter

Stoobie 

Hi,  thanks for the reply. I changed the resolution to 720 and it works. Unfortunately, I have no sound. Does the sound work through the dvi, or do I need a different adapter. 

My control is beo 4 and I connected it to the TV selection on the controller. 

My STB is a MAG254. It doesnt have audio connection but it does have an IR input.

Nearly there, just need sound. Hope someone can help.

Thanks again, Jude

Hi,  thanks for the reply. I changed the resolution to 720 and it works. Unfortunately, I have no sound. Does the sound work through the dvi, or do I need a different adapter. 

My control is beo 4 and I connected it to the TV selection on the controller. 

My STB is a MAG254. It doesnt have audio connection but it does have an IR input.

Nearly there, just need sound. Hope someone can help.

Thanks again, Jude

No DVI doesnt carry sound.

You might want to get a HDMI sound extractor. HDMI carries sound and image. The extractor will extract the sound and carry it over a digital audio cable to the digital audio ports in the back. (a1 - a4)

Though, that should work, I am currently struggling with getting it to work as well. But it should work in theory.

If I recall correctly you will not get sound in via the DVI connector. I think you also have to connect using RCA cables. The user manual for your STB shows that cable. 

From reading about your STB there looks like an AV out (looks like a headphone socket) so with the correct cable from there to the TV it should work. In the TV connections menu you may have to link the inputs. 

Stoobie