Let me start off by saying I played Stonekeep as a kid and it is/was the bees knees. I have encountered an issue though. Game runs fine while playing, however, as soon as I quit the game will exit to my normal desktop then the screen will turn black. The odd thing is that I can CTRL ALT DEL and that will restore my desktop for a few seconds then it will pop back to black screen. I have to hard reset a couple of times in order for the issue to resolve itself. Any ideas on the problem?

Strange behavior, considering it happens on exit. Do you experience something similar with other DOSBox games or maybe with other software?

Honestly I think your PC is suffering some hardware related issue, but if you're experiencing the black screen problem only with Stonekeep, you could try setting another render output. Run the GOG DOSBox configuration tool ("Graphic mode setup" in the Start menu) and try changing the graphic mode and/or the scaling engine.