Hi Alan --
I don't have any experience with Digital Tool machines, but you might want to take a look at a couple of threads that appear to be related. See this one on the Digital Tool 904:
Digiital tool 904 ...or this one
Both are pretty recent threads, and might put you in touch with others who share your plight.
If the original DOS computer is with your machine it is unlikely that you can upgrade that hardware to run Windows because of the processor, speed, RAM, etc. The controller may also likely need to be upgraded for windows as well as all the control software. In any event you will probably need some details such as the model number, software versions (if any), to get more specific help.