Open pdf file selected from excel

I am using this code to select a folder and diplay the pdf files in that folder..

Sub SelectPdfFile()
    Dim fn As Variant
    Dim i As String
    i = InputBox("Enter Job Number", , "Job Number")

    P = "C:\" & i & "\"
    ChDrive P
    ChDir P


    fn = Application.GetOpenFilename("PDF Files,*.pdf", _
                                     1, "Select Truss Picture", , False)
    If TypeName(fn) = "Boolean" Then Exit Sub    ' no selection
    Debug.Print "Selected file: " & fn
    Workbooks.Open fn
End Sub

Of course when I select a pdf, excel opens it and it becomes gibberish.
How can the select file be opened with acrobat reader?
xl2000