Halloween is around the corner, and to get you into the mood, Microsoft has released a Eerie Autumn theme pack for Windows 7 which can be downloaded from the Windows 7 Personalization Gallery.
“Scared much? Gargoyles, gourds, and ghostly creatures haunt this eerily elegant Windows 7 theme.”
The sound scheme is pretty scary too; especially the one associated when Windows throws up an error! 
If you want to save its wallpapers, you can get them from the following folder:
E:\Users\username\AppData\Local\Microsoft\Windows\Themes\Eerie Aut\DesktopBackground
You will have to show hidden/system files first from the Folder Options.
Download Page : Microsoft.
You may also want to check out other Halloween themes!
Thank you for sharing my most favorite time of year!