Private Sub Worksheet_Change(ByVal Target As Range)
If Not Intersect(Target, Range("a1")) Is Nothing And Range("a1") = 1 Then
cdo = CreateObject("cdo.message")
cdo.to = "someone@some.com"
cdo.from = "me@myhost.com"
cdo.Subject = "cdo test"
cdo.textbody = "this is the content " & Range("b17").Value
cdo.send
End If
End Sub