>But... It's still necesary to run Clipper (DOS)
>
>It doesn't work. NTVDM executes multiple times as CONHOST but program doesn't run.
>
>I found hundred of questions about this in millions of forums but most of them only explain what NTVDM process is. I want to know how do I do for running DOS window again!

Alternately, you may download DosBox (I think it's on http://www.dosbox.com/download.php?main=1) and then you can run your DOS stuff regardless of any settings outside.