As Glenn pointed out, there are several already completed UDFs readily available for handling services. But here is a small example that I just wrote up that accomplishes what you specifically asked for. You can play around with it, and look at Glenn's suggestions for more advanced options.

 Code:
$ServiceStatus = IsServiceRunning("wuauserv")

If $ServiceStatus[0] = "Running"
   ? "Automatic Updates is Running"
   If InStr($ServiceStatus[1],"Auto")
      ? "Automatic Updates is set to Auto"
   Else
      If ChangeServiceState("wuauserv","Automatic")=0
         ? "Automatic Updates Has Been Set to AUTO"
      Else
         ? "Error Setting Automatic Updates to AUTO"
      Endif
   EndIf
Else
   If ChangeServiceRunState("wuauserv","Start")=0
      ? "Automatic Updates Has Been Started"
      If ChangeServiceState("wuauserv","Automatic")=0
         ? "Automatic Updates Has Been Set to AUTO"
      Else
         ? "Error Setting Automatic Updates to AUTO"
      EndIf
   Else
      ? "Error Starting Automatic Updates, Still not Running"
   EndIf
EndIf

get $

Function IsServiceRunning($svc)
; Returns a 2 element array with the Running status[0] and the start mode [1]
   $objWMIService = GetObject("winmgmts:{impersonationLevel=impersonate}!\\"+@WkSta+"\root\cimv2")
   $colListOfServices = $objWMIService.ExecQuery("Select * from Win32_Service WHERE Name='$svc'")
   For Each $objService in $colListOfServices
      $IsServiceRunning = $objService.State,$objService.StartMode
   Next
EndFunction

Function ChangeServiceState($svc,$state)
;Call function with either 'Automatic','Manual', or 'Disabled'
   $objWMIService = GetObject("winmgmts:{impersonationLevel=impersonate}!\\"+@WkSta+"\root\cimv2")
   $colListOfServices = $objWMIService.ExecQuery("Select * from Win32_Service WHERE Name='$svc'")
   For Each $objService in $colListOfServices
      $ChangeServiceState = $objService.ChangeStartMode($state)
   Next
EndFunction

Function ChangeServiceRunState($svc,$runstate)
;Call function with either 'Start' or 'Stop'
   $objWMIService = GetObject("winmgmts:{impersonationLevel=impersonate}!\\"+@WkSta+"\root\cimv2")
   $colListOfServices = $objWMIService.ExecQuery("Select * from Win32_Service WHERE Name='$svc'")
   For Each $objService in $colListOfServices
      If $runstate="Start"
         $ChangeServiceRunState = $objService.StartService()
      Else
         If $runstate="Stop"
            $ChangeServiceRunState = $objService.StopService()
         Else
           Exit 87
         EndIf
      EndIf
   Next
EndFunction