Perhaps you could place a flag file somewhere
beyond a regular user's area of access and
use an IF statement to check for the
existance of the file to determine whether
or not SMS is run on the PC. This maintains
the requirement of being based on the PC
itself.

Example:

IF EXIST ("%windir%\system32\smsflag.txt")
GOTO "SMS"
ELSE
GOTO "END"
ENDIF

I hope this helps!

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