open System
open System.Runtime.InteropServices
open Shell32

let shell = new Shell32.ShellClass() 
let vRootFolder = Shell32.ShellSpecialFolderConstants.ssfWINDOWS
let folder = shell.BrowseForFolder( 0, "Hello, COM(F#) World!", 0, vRootFolder )
if folder  null then Marshal.ReleaseComObject( folder ) |> ignore
Marshal.ReleaseComObject( shell ) |> ignore