How to check cell isnt blank upon saving or closing and color code them to show blanks

Could anyone expand on this a bit?
If input is entered into column C (range C2:C100), then row cells for columns D, E ,F, H or I must NOT be blank upon save.
Could be that one or more of these row cells are left blank by mistake.

An error msg pops up upon attempt to save and colors each cell yellow that lacks info.

I found this coding in another thread.

Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As Boolean)
Dim rngCell1 As Range
Dim rngCell2 As Range
Dim strSheet As String
Dim varResponse As Variant
    
    Cancel = False
    'set cells to check:
    strSheet = "Sheet1"   'name of the sheet you want to check.
    varResponse = Empty
    rngCell1 = Worksheets(strSheet).Range("A2")
    rngCell2 = Worksheets(strSheet).Range("B3")
    
    If rngCell1.Value = Empty Then
        varResponse = MsgBox("You must enter a value in cell " & rngCell1.Address, vbCritical + vbOKOnly)
        Sheets(strSheet).rngCell1.Select
    ElseIf rngCell2.Value = Empty Then
        varResponse = MsgBox("You must enter a value in cell " & rngCell2.Address, vbCritical + vbOKOnly)
        Sheets(strSheet).rngCell2.Select
    Else
        'continue code here ..
        GoTo CompleteExit
    End If

    Cancel = True

CompleteExit:
    Cancel = False

End Sub