Check a checkbox when an item in a combobox is selected

[TensE]

How do I make specific checkboxes be checked when I select an entry in a combobox? Like if I select entry 1 checkbox 1 and 3 will be checked if entry 2 then 3 and 4 be checked? So far I'm encountering a problem that when I change the combobox entry the checboxes that were checked stay checked.

Here's the code from the sub it's related to if that helps

Private Sub getProgramsNamount(strProgID As String, dblDuration As Double)
   Dim strProgramName As String
   Dim dblPrice As Double

    If strProgID.Contains("N") Then
       strProgramName = "None"
    End If

    If strProgID.Contains("C") Then
       strProgramName = "Cycling "
       dblPrice = dblDuration * 10
    End If

    If strProgID.Contains("W") Then
       strProgramName = strProgramName + "Weight Loss "
       dblPrice = dblPrice + (dblDuration * 15)
    End If

    If strProgID.Contains("K") Then
       strProgramName = strProgramName + "Kick Boxing"
       dblPrice = dblPrice + (dblDuration * 25)
    End If