Weird...
What happens if you create a batch file for starting the second program, and execute the batch file with QProcess? The usual way is to pass the batch file as parameter to cmd.exe.

EDIT: perhaps there's a problem with spaces in the path. Can you try with:
Qt Code:
  1. QString sFullPath( "C:\\Progra~1\\Net3Helper\\Net3Helper.exe" );
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?