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
Y luego usarlo con:
dim res as long
res = ShellExecute(Me.hwnd, "Open", "c:\documento.doc","", "", 1)