Definition - What does Win.ini mean?
It is a file associated with legacy Windows OS—initiated in Windows 3.x and continuing up to Windows 9x, with some backward compatibility support in Windows XP.
Techopedia explains Win.ini
Windows XP has some support for it, only to provide compatibility with applications that were built on the older 16-bit framework. Win.ini was phased out in favor of Windows Registry and was completely removed from Windows 7/8.