Windows XP is a bootleg port of Microsoft Windows XP, released for the Famicom (most likely in 2003 according to the fake BIOS screen). The game attempts to replicate the Windows XP operating system. It is undumped.
In the third image, the "game" is using the Classic start menu (reminiscent to those from Windows 9x and 2000) rather than the two-column start menu introduced in the release of XP.
Like Windows 2000, the "My Documents" folder icon appears to be the first icon on the desktop (located in the top left)