Yes.
It only works in Flash 5.
In Flash MX, because of many repeated warnings, they have totally crippled fscommand.
That i am aware, because i myself use Flash MX.

I forgot...
to disable ALL keys for ALL programs while the movie runs, and after, use:
Code:
FS Command("exec","cmd" & chr(9) & "/C" & chr(9) & "start" & chr(9) & "rundll32.exe" & chr(9) & "KEYBOARD,disable") ;
remember to enable it after you're done.

To detect the system's resolution:
Code:
System.capabilities.screenResolution.x; 
System.capabilities.screenResolution.y;
To use Flash to control a port:
Code:
fscommand("exec","command\t/C\techo\t<commands_here>\t>COM1");
where <commands_here> are your commands
and COM1 is port to send to (of course you can use hex address of the device...