Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim intSelSheet As Integer
' Check the cell to see if it's fill colour's changed to red,
' If so, set the 1st checkbox to on.
If Range("F3").Interior.ColorIndex = 3 Then
chkCellColour1.Value = True
chkCellColour2.Value = False
' Otherwise, check if it's blue & set the other checkbox
' (turning the first checkbox value to off).
ElseIf Range("F3").Interior.ColorIndex = 5 Then
chkCellColour1.Value = False
chkCellColour2.Value = True
' Finally, if the cell has bot been filled with blue
' or red, turn both checkboxes to off.
Else
chkCellColour1.Value = False
chkCellColour2.Value = False
End If
End Sub