Does it give you an error message or anything? This is a shot in the dark, but take a look at this article:
PRB: Windows NT 4.0 May Close FoxPro for MS-DOS Application

>I have the opportunity of converting an app done in FoxPro 2.6 for DOS to VFP. However, I cannot get the old application to run on my machine running NT 4.0. It was shown to me on a Win '95 machine. Is there a way to get it to run in NT 4.0?