This is what I have come up with the compilation from both Glenn and Mart. Again many thanks for your comments

 Code:
$systemdrive = SUBSTR($windir,1,2) ; -- This will show C: or M: or what drive Windows is installed on
$InstRoot = '\\usmiadc01\Software$\Lync\'

$Is64 = If($systemdrive+'\Program Files (x86)')

If InGroup('Lync_Users')
   If Not Exist $systemdrive+'\program files\microsoft office 15\root\office15\lync.exe')
   OK to Install Lync
	Else 	  
	; set the installer based on the platform bitness
  	If $Is64           ; running on x64 platform
    	$Install = '\setup.exe /configure configuration-en-64.xml'
 	 Else	
   	 $Install = 'setup.exe /configure configuration-en.xml'
  	EndIf

  	; run the installer
  	'Running: ' $InstRoot $Install @CRLF
   	;RUN $InstRoot + $Install
    Else
     ?"Lync already installed"
    EndIf
Else
  'No Lync for you!' @CRLF
EndIf



But im still getting a syntax error when I call it \:\(

Edited by Mart (2015-08-20 05:51 PM)
Edit Reason: Added code tags.