Hosts "Windows Whistler Source" files, which include these fan-made startup and shutdown themes.
Some versions include sound bites from obscure Microsoft-published titles to add a unique "whistle-like" quality. Where to Listen and Download windows whistler fake startup sound download
Note: I can’t host files directly, but search the exact phrases above + “download” and you’ll find them. Hosts "Windows Whistler Source" files, which include these