I'm guessing you don't want a permament change, since that would mess with games which require expanded memory.
Type in the following command:
ems=false
to temporarily disable expanded memory for the current DOSBox session.
How to, for
really computer unsavy:
1. Download this:
http://www.abandonia.com/vbullet/att...4&d=1209413074
2. Unpack it into the directory you mounted as your C drive in DOSBox
3. Run DOSBox and mount your C drive.
4. Type in
memory and press Enter.
5. You'll see a simple menu for changing EMS/XMS/UMB setting. Change the settings you need to and exit the menu
6. Run the game