shell default application to open a file

how do you shell a document instead of an application so that it opens with the default application for openiong files of that filetype. Basically what i a trying to do is shell a word document so it loads word or wordperfect. I cant be arsed to mess about with the registry anymore.

Code:

---

Private Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" (ByVal hwnd As Long, ByVal lpOperation As String, ByVal lpFile As String, ByVal lpParameters As String, ByVal lpDirectory As String, ByVal nShowCmd As Long) As Long
Const SW_SHOWNORMAL = 1
Private Sub Form_Load()
    ShellExecute Me.hwnd, vbNullString, _
    "c:\myfile.doc", vbNullString, "C:\", SW_SHOWNORMAL
End Sub

---