I recorded a macro to add a comment to a cell. This works fine as a
standalone macro.

When I add it to an existing sub routine. I get "Run-time error'1004'
Application-defined or object-defined error" The help file doesn't live up
to it's name on this one.

Can anyone help, please?

Private Sub ComboBox1_Change()
Application.ScreenUpdating = False
If Right(ComboBox1.Text, 3) = "D16" Or Right(ComboBox1.Text, 3) = "D32" Then
Range("P37").Select
ActiveCell.FormulaR1C1 = "Delta software operation"
' Add comment code
Range("P37").Select
Range("P37").AddComment
Range("P37").Comment.Visible = False
Range("P37").Comment.Text Text:="Check image acquisition, recall and
manipulation."
'
Range("P38").Select
ActiveCell.FormulaR1C1 = "Image quality"
Range("P39").Select
ActiveCell.FormulaR1C1 = "Network operation"
Range("P40").Select
ActiveCell.FormulaR1C1 = "PC operation"

Range("P37:R40").Select
Selection.Borders(xlDiagonalDown).LineStyle = xlNone
Selection.Borders(xlDiagonalUp).LineStyle = xlNone
With Selection.Borders '(xlEdgeLeft)
.LineStyle = xlContinuous
.Weight = xlThin
.ColorIndex = xlAutomatic
End With

Range("U37:V40").Select
Selection.Borders(xlDiagonalDown).LineStyle = xlNone
Selection.Borders(xlDiagonalUp).LineStyle = xlNone
With Selection.Borders
.LineStyle = xlContinuous
.Weight = xlThin
.ColorIndex = xlAutomatic
End With

Else
'CheckBox74.Visible = False
End If