Powerpoint VBA dont close Excel - vba

Question

My VBA code in Powerpoint wont "kill" my excel application.
it still runs if i have a look in task manager.
I would like to close it the right way rather than kill.
Anyone that could help me? I already searched and tried to get it working but with no luck.
Public Sub OnSlideShowPageChange(ByVal Wn As SlideShowWindow)
If Wn.View.CurrentShowPosition = 2 Then
Dim xlApp As Object
Dim xlWorkBook As Object
Set xlApp = CreateObject("Excel.Application")
xlApp.Visible = False
Set xlWorkBook = xlApp.Workbooks.Open("D:\ELE_powerpoint\book1.xlsx", True, False)
With xlWorkBook.ActiveSheet
txt1 = xlWorkBook.sheets(1).Range("A2")
txt2 = xlWorkBook.sheets(1).Range("A3")
txt3 = xlWorkBook.sheets(1).Range("A4")
End With
ActivePresentation.Slides(2).Shapes("a2").TextFrame.TextRange = txt1
ActivePresentation.Slides(2).Shapes("a3").TextFrame.TextRange = txt2
ActivePresentation.Slides(2).Shapes("a4").TextFrame.TextRange = txt3
Set xlApp = Nothing
Set xlWorkBook = Nothing
End If
End Sub

Answer 1

Try xlApp.Quit before Set xlApp = Nothing

Answer 2

Set xlApp = Nothing
That instruction sets the xlApp object reference to Nothing. It doesn't destroy the object it's referring to, but it prevents further code from using that reference.
Excel is a rather complex application; creating an instance of an Excel.Application object has many implications, and in order to properly shut itself down, it needs to run through a certain sequence of instructions (unload Excel and COM add-ins, close any opened file, tear down the VBE if it was initialized - which in turn may need to tear down its own add-ins, etc.) - by setting your reference to Nothing, you say "I don't need it anymore" - but what of the COM add-ins that still use it? That workbook that's still open is a Workbook object with an Application property that also references the very same object you were referring to - and these references aren't gone yet!
As Tim and Tom said, you need to call the Quit method of the Excel.Application instance, so that it can clean itself up.
And if that's the last thing your code does, then you probably don't even need to Set xlApp = Nothing, since the VBA runtime will know that it doesn't need to hold on to the xlApp reference after it's out of scope; Set xlWorkbook = Nothing is superfluous as well.
Quitting Excel will close the unmodified workbook you've opened, but since you opened it, I'd argue that it's good form to close it yourself - just call xlWorkbook.Close before you call xlApp.Quit.