5days is made with
AGS. It's a Windows game, so you shouldn't use DOSBox. Out of the box it tries to set the video to 320x200, which was already ludicrous when the game came out, and may be of course not supported in many modern systems.
I think running the setup program included with the game, and choosing a different video mode that's supported by your hardware and OS, should solve the problem.
Of course you can even get this video mode supported in an older (virtual) machine, but I think the game should work on any Windows version, if you run the setup program first and change the video.