We have a software created for an enternainment machine under DOS. It works fine. It has a deskey (on the printer port) to avoid changing the programing on the machine. We can only run the games that were created but need to make new ones. Software has to be decompiled, changed and recompiled. it is about 200k to 300k. I think originaly it was done under Borland. I can open the program but as I am not technical enough, I cannot change it properly.