I can send you my config file later tonight when I'm back on the computer that has it.
As further proof that I can indeed be a complete idiot sometimes, it only occurs to me now that you don't have to wait another 4+ hours for me at all.
Since the config I'm using is just the default one that DOSBox shipped on (at least I think that's the case, if I remember correctly), all you'd have to do is:
1) backup the config you have right now (or basically, backup the custom config you were using for that other game)
2) uninstall and reinstall DOSBox
Step #2 will effectively reset the configuration back to the original. Isn't that easy?
Oh, and a lesson to make a backup of the config file every time you make any changes to it!
Incidentally, you might want to browse the DOSBox forum and ask if there're ways you can create a Windows shortcut (or whatever equivalent your OS uses, if it's not Windows) for DOSBox to use a specific config file. Then you can create 2 shortcuts, one for Lemmings-DOSBox, and the other for your-other-game-DOSBox. I'm pretty sure there should be a way to do this, since config files are so important in getting certain games to work.
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P.S. Yet another advantage of DOSBox that I have completely forgotten...they have versions of it for other OSes besides Windows! Whereas VDMSound is Windows-specific. Indeed, that's one more evidence why VDMSound is probably useless inside DOSBox.