With Directx you can have two types of Graphic Devices: HAL and Reference; and you can have two types of Vertex Processing: Hardware and Software.
See this article to check what all those are, what they do and when to use them. Hope that helps. The Reference Device is provided as a debug tool and any machine using an application or game that use that Device type must have installed the Directx SDK or at least the Debug version of Directx (provided with the SDK).
http://msdn2.microsoft.com/en-us/library/bb219625.aspx
Edit: for the scenario you are describing, you may want to create a HAL Devive and Software Vertex processing as a fall-back option (Hardware Verxtex processing should be your default).