I know this is not the right place for the question, but since this is the only forum I know and use frequently.

I still have Clipper (DOS) app, which I run from the command windows.
I don't know what happened, when I run the app today, it didn't give any respond (go back to C:\). then I tried all the DOS app I know, such as old Norton Utility, PKzip, etc, same thing, no respond and nothing happened.

What has happened? is this caused by virus? or setting in Windows?

Desperately need help

thanks

Jerry