VBA to open a workbook with manual calculation and close with automatic calculation

I have a very large workbook with several worksheets. All have extensive formulas and conditional formatting. Data entry is very, very slow. Is there any code that I can add to my existing VBA that would open the workbook set to manual calculations so that data entry is not bogged down? And then close (or save) the workbook by reactivating calculations to automatic? My current VBA code is listed below. Thanks to any help you could provide.

Private Sub CommandButton1_Click()

Worksheets("Master Membership Records").Range("B5:B525").ClearContents

End Sub
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    Dim Xrw As Long, Lr As Long
    If Target.Row = 3 Then
        Application.EnableEvents = False
        Lr = Range("A" & Rows.Count).End(xlUp).Row
        Range("A5", "Q" & Lr).Sort key1:=Cells(5, 1), Header:=xlNo
        Xrw = Range("A:A").Find("X", , , , , , False, , False).Row
        Range("A5", "Q" & Xrw - 1).Sort key1:=Cells(4, Target.Column), Header:=xlNo
        Range("A" & Xrw, "Q" & Lr).Sort key1:=Cells(4, Target.Column), Header:=xlNo
        Application.EnableEvents = True
    End If
End Sub

bakerman2, that did not do anything. Unless I am placing it in the wrong way. I am a novice.

Wonderful solution! Thank you so much bakerman2!