A total of five theme packs are available for free download. They each contain a number of background images that show an anime lady. There are several variants available, with a range of full-bosomed vamp up to chastise Business Lady.

The theme packages are diverse in sound files that replace the standard Windows sounds. If, therefore, for example, a fatal error occurs, it is not only issued a simple warning. Instead, an excited woman's voice makes in Japanese attention to a problem.
For users of Windows XP and Windows Vista, Microsoft Japan is the sound files available for download individually. The files can then be assigned by hand, certain system events. This works on Windows 7 of course automatically. The new theme packs are likely to be primarily of interest to anime fans.
Download: Windows 7 Anime Theme Packs by Bing Japan
Download: Complete Package (30MB)
Source: Winfuture