I am trying to get Ultima Underworld to work in DOSBox, and it works great the first time I run it. But then, every subsequent time I try to run it, or after I close DOSBox and reopen it, the screen is completely chopped up and the music gets garbled, and it's really slow. I can't find any way to stop this from happening unless I reset my computer and run DOSBox again, freshly. I've relatively certain I close DOSBox completely the first time. How can I stop this from happening?