Why do you need the path? So that you can run it? If so, then here is a handy way of doing so (presented in VB format, since that's my background...)
Option Explicit
Private Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" (ByVal hwnd As Long, ByVal lpszOp As String, ByVal lpszFile As String, ByVal lpszParams As String, ByVal lpszDir As String, ByVal FsShowCmd As Long) As Long
Public Sub OpenMail()
ShellExecute 0&, "Open", "mailto:", "", "", 0&
End Sub