Open file based on user selection

Greetings, Gurus.

A search of the forum gave me most of the code I need, I just need some help with modification. The code below opens a window which allows the user to select a file to open. Apparently, it starts in the directory of the file containing the macro. How would I modify this to open in "M:\Archived PO Responses\Processed\"?

    On Error GoTo NoPO
    NewFN = Application.GetOpenFilename(FileFilter:="Excel Files (*.xls), *.xls", Title:="Please select a file")
    If NewFN = False Then
    'They pressed Cancel
    MsgBox "Stopping because you did not select a file"
    Exit Sub
    Else
    Workbooks.Open Filename:=NewFN
    End If
    On Error GoTo 0

Thanks in advance for any help you can offer.

Hutch