Is it the Megs Graduation file you are trying to open?
This file is seen as something that VLC can open, so what happens if you double click on it?
If it doesn't open then what error do you get?
If no error then right click on the file and select Properties from the drop down menu. Click on the Details tab and scroll down to find File, Item Type. This should give us the details on what format the file is and we can hopefully find a way to open it.
I think that version of sonic my dvd may be considered abandonware, a v4 version is on the internet archive site. You could try installing that on your win 10, set the compatibility properties of the programs .exe to win xp.
If that fails you can install Oracle Virtual Box and set up a virtual machine with win xp and run the software through that, export as dvd .iso image.
The software that we all used for this type of job worked very well on XP. This was the very reason I kept a couple of old Pc's with XP on [ no Service Packs] ,There is tons of software on them for creating slideshows, video's etc ,them putting them onto the old format ......DVD's . The software includes DVDSanta, Sonic DVDit and lots of others. The problem now is the newer formats of video....mp4, divx are not recognised by these old XP PC's. So ,I now cannot convert mp4 files to put onto DVD disk's . Just as well though , as DVD'd are not the best media for storage . My mp4 footage etc that I get from my drone cameras are edited and just encoded back to mp4. Ideal to put onto USB pen/flash drives as most TV's will read them .
From the description of the file extension .dvd, my understanding is that is just a directory file that tells the software whrere to obtain the data files and where they are to be saved etc. It is not an actual media file. I think you need to obtain the actual DVD disk containing the slide show created with the software. It may be possible to read the data from the orignal slideshow disk using modern software.
Need to have a look at the actual DVD file structure and post up what file(s) and extensions are there.
What file extention is Megs Graduation?
As MarkE19 has suggested, you need to find the extension type. In terms of DVD file structures ,they can be ifo's, bups,etc , but normal video files can be .mov, avi, mpeg,mp4 , there is loads of them. It is very important to find out what these files are. Operating systems by default hide these file names [extensions[ I allways uncheck the box .....hide extension for known file types....
It is one of the most important things in computing.ie understanding what extension a file has.
Photo's for instance an be a number of things, bmp, png, raw, gif , jpg etc. If you can understand the file extension it will help you choose what type of software you need to use it.