Hello SoteriaLive,

When using the With ... End With construct, all members that belong to the object following With must be prefixed with a period.
Private Sub Worksheet_Change(ByVal Target As Range)

    Dim i As Integer

        If Target.Address <> "$E$5" Then Exit Sub


        With Sheets("Shop Order")

        '  The following code works with page 2 of the shop order worksheet specifically with System B.
      
        '  In this first if statement, it is assumed that system B will not be in use at all.

            If .Range("A73") = "" Then
    
                .Range("C71:N74").Borders.LineStyle = 0              'this comment clears out all boxes for system B
    
            End If
     
        '  the following code creates one thick outline box because this carriage will have only one section.

    
            If .Range("A73") <> "" And Range("I46") >= 1 Then
        
                .Range("E72:N74").Borders.LineStyle = 0           '  This line clears out all boxes for system B after the first carriage box
         
                With .Range("C72:D74")                            '  This line draws in 1 thick border box spanning two columns and three rows.
            
                 '  Remove all diagonal borders
                    .Borders(5).LineStyle = xlNone
                    .Borders(6).LineStyle = xlNone
                    .Borders(11).LineStyle = xlNone
                    .Borders(12).LineStyle = xlNone
                
                 '  Add borders around each cell
                    For i = 7 To 10
                        With .Borders(i)
                            .LineStyle = xlContinuous
                            .ColorIndex = 0
                            .TintAndShade = 0
                            .Weight = xlMedium
                        End With
                    Next i
                
                End With
        
            End If
        
        End With
        
End Sub