GIGO :) Never seen a program or path that begins and ends with quotes as part of it, or quotes followed by a backslash
$nonsense = q{"C:\PROGRA~1\MOZILL~1\firefox.exe"\ };
qx{ $nonsense };
__END__
'"C:\PROGRA~1\MOZILL~1\firefox.exe"\' is not recognized as an internal
+ or external command,
operable program or batch file.