Diablo 1 HD Hellfire Mod | Awake

So I started playing the game recently, and when I went to full screen mode, everything seemed fine (before I was not using full screen). However, after I stopped playing, the next time I tried to open Belzebub it did not work. It gave me a message that says, "File not found. Program requires 'diabdat.mpq' to run." I have not deleted any files, and the only thing I did differently from the previous times I played was make the game full screen.

I am using Diablo v. 1.0 as my base and I use Windows 10. I was not sure if I was supposed to install the updates for this to work optimally or not, so I did not.

Any suggestions on how to fix this? As it is, I will never even get to see the Butcher's Chambers. Tragedy. Help?

Thanks

Copy that diablo.mpq from the D1 cd to any folder and add the files from http://diablo1.ovh.org/hd/?download This is all you need really, but you can install D1 if you really want to play the original unmodded game, thou you will still need to copy the diablo.mpq to the installation folder if you want to play without the cd, that's how games ran ~20 years ago.