I want to help. I am not that familiar with the EX2040 software as I am the D100 software. Which one are you trying to use? Is it the software in Post 46 or Post 47? I know the D100.zip program does not require a key and I don't think that the EX2040 one does either. I like the D100 program better only because I have used it more. You must start either program by clicking on the D10.bat file for the D100 software and the PDD.bat program for the EX2040 software. After that, both programs are no longer windows type programs. Therefore, everything is keyboard operated. The mouse is no longer used. By the way, just ignore that .reg file, it is a pre-windows program extension and is not a "key" type file. Also, I may be wrong but I think that your folder path is OK, but, I would recommend that the EX2040 be put in the root directory, like this. C:\EX2040.
Please come back with any questions that you might have.