Thanks for the thoughts... mostly I'm programming in an old compiler program called Clipper. Using the edit program called "Q" causes the problem, as does linking using the linker program RTLink. Running the compiler (Clipper) doesn't cause a problem, and running the resulting compiled Clipper program usually doesn't cause the problem. I use a batch file to call the compiler and linker, but run Q directly. I tried running Q in the directory it resides in, and the same thing happens... "Cannot load command.com... system halted".
Q is q.com, a shareware program Ive used for 15 years. (Which doesnt make me a computer expert!)
The batch file is simply:
clipper %1 > ERFIL /B
IF NOT ERRORLEVEL 1 RTLINK FI %1, HELP LIB CLIPPER, NANFOR, CPMI
Thanks for the help!