Drop List Zoom Program Not Working

I've tried using all the formulas from: http://www.contextures.com/xlDataVal08.html
and they will not work. I can't figure out why.

Your code has a Reference error

=ROUND(IF(AND(OR(ISBLANK(C5),ISBLANK(C4),ISBLANK(C3),ISBLANK(#REF!))),"",C5-C4),4)

Select the field where the #REF should be pointing to.

You could use the below calculation to produce a zero, if field B5 or C5 is blank/empty

=IFERROR(ROUND(IF(AND(OR(ISBLANK(B5),ISBLANK(B4),ISBLANK(B3))),"",B5-B4),4),0)

Or use the below calculation to show nothing/blank field, if field B5 or C5 is blank/empty

=IFERROR(ROUND(IF(AND(OR(ISBLANK(B5),ISBLANK(B4),ISBLANK(B3))),"",B5-B4),4),"")

Still a work in progress but here what I found to work thus far. With a little code manipulation, the code could actually do what you want.

* You must select an empty cell to reset the zooming

Source: https://www.youtube.com/watch?v=r65mICOUQcA

There are 3 codes

Code #1:

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Zoom_Cells
End Sub

Code #2:

Sub Zoom_Cells()
  Dim sel As Range, cell As Range, zoom_in As Single
    Set sel = Selection
    zoom_in = 1.25  'Zoom rate
    
    For Each cell In Selection 'if there are blank cells in selection, shapes are deleted and ended method
      If cell.Value = Empty Then
      Call remove_picture
      GoTo here:
      Exit Sub
      End If
    Next
    
    Call remove_picture  'Remove any existing zoom piture
      Application.ScreenUpdating = False
      sel.CopyPicture Appearance:=xlScreen, Format:=xlPicture 'Create zoom picture
      ActiveSheet.Pictures.Paste.Select
        With Selection
         .Name = "Zoom_Cells"
           With .ShapeRange
            .ScaleWidth zoom_in, msoFasle, msoScaleFromTopLeft
            .ScaleHeight zoom_in, msoScaleFromTopLeft
              With .Fill
               .ForeColor.SchemeColor = 44
               .Visible = msoTrue
               .Solid
               .Transparency = 0
              End With
           End With
        End With
here:
    sel.Select
    Application.ScreenUpdating = True
    Set sel = Nothing
End Sub

Code #3:

Sub remove_picture()
 Dim k As Object
   For Each k In ActiveSheet.Pictures
     If k.Name = "Zoom_Cells" Then
      k.Delete
     End If
   Next
End Sub