running an old DOS game on Windows Vista

My little cousin got a very old DOS game. So they wanted to play this on a
Laptop with Windows Vista.

The problem on starting, was, that the system said "fullscreen mode is not available on this system"

After a little searching, I found some hint's about installing Windows XP drivers´, but that
can cause an instable system.
The other link of help was DOSBox. This is a x86 PC emulator.
You can configure a lot of things.
But on Vista, the problem is with the access rights. So you have to execute the dosbox as
Administrator, so that the config could be written as describe in the readme.
I have change the keyboard layout to german and also the language.

To use directories from the host os, you have to mount it.