Example of stopping and uninstalling service using nsis

stopAndUninstallService.nsi

!define APPNAME "App Name"
!define COMPANYNAME "Company Name"
!define DESCRIPTION "A short description goes here"
# These three must be integers
!define VERSIONMAJOR 1
!define VERSIONMINOR 1
!define VERSIONBUILD 1
# These will be displayed by the "Click here for support information" link in "Add/Remove Programs"
# It is possible to use "mailto:" links in here to open the email client
!define HELPURL "http://..." # "Support Information" link
!define UPDATEURL "http://..." # "Product Updates" link
!define ABOUTURL "http://..." # "Publisher" link
# This is the size (in kB) of all the files copied into "Program Files"
!define INSTALLSIZE 7233
 
RequestExecutionLevel admin ;Require admin rights on NT6+ (When UAC is turned on)
 
InstallDir "$PROGRAMFILES\${COMPANYNAME}\${APPNAME}"
 
# rtf or txt file - remember if it is txt, it must be in the DOS text format (\r\n)
; LicenseData "license.rtf"
# This will be in the installer/uninstaller's title bar
Name "${COMPANYNAME} - ${APPNAME}"
;Icon "logo.ico"
outFile "sample-installer.exe"
 
!include LogicLib.nsh
 
# Just three pages - license agreement, install location, and installation
page license
page directory
Page instfiles

!macro VerifyUserIsAdmin
UserInfo::GetAccountType
pop $0
${If} $0 != "admin" ;Require admin rights on NT4+
        messageBox mb_iconstop "Administrator rights required!"
        setErrorLevel 740 ;ERROR_ELEVATION_REQUIRED
        quit
${EndIf}
!macroend
 
function .onInit
	setShellVarContext all
	!insertmacro VerifyUserIsAdmin
functionEnd
 

!macro stopAndUninstallService serviceName

  DetailPrint "Hello ${serviceName}"
stopService:
	
	SimpleSC::ExistsService "${serviceName}"
	Pop $0
		${If} $0 == 0
		  SimpleSC::ServiceIsRunning "${serviceName}"
		  Pop $0
		  Pop $1 
		  ${If} $1 == 0 
			goto RemoveService
		  ${Else}
			SimpleSC::StopService "${serviceName}" 1 30
		  ${EndIf}
		 SimpleSC::ServiceIsStopped "${serviceName}"
	  Pop $0
	  Pop $1 
		${If} $1 == 1 
			goto stopService
			${Else}
				goto RemoveService
			${EndIf}
	 RemoveService:
	 	SimpleSC::RemoveService "${serviceName}"
			
	${Else}
	  
	  DetailPrint "$0 does not have service '${serviceName}'"
	
	${EndIf}

!macroEnd


section "install"
	!insertmacro stopAndUninstallService "DemoServiceName"
sectionEnd