If you got a request to do this then it is more than likely that your system is old and it is not installed. This is true to the older versions of PIIand PIII chipsets.
It is actually controlled by your graphics and may be possible to try updating the graphics within your system to a newer/faster graphics card. If your system does not support this upgrade then you may have to just opt to looking at not playing Dungeons and Dragons online as a massively multiplayer onlinegame.