Vista
In short
Windows Vista was a major operating system released by Microsoft in early 2007. It succeeded Windows XP and introduced a new visual style and improved security features.
In plain words
It was the software that ran many computers in the mid-2000s. It changed how windows and menus looked on the screen. However, many people found it slow and difficult to use at first.
A simple example
A user might have seen many pop-up boxes asking for permission every time they tried to install a new piece of software.
Why it matters
It introduced many modern features like the taskbar search and improved graphics support. It also set the stage for the much more successful Windows 7.
Easy to mix up
Do not confuse it with the 'Vista' view in photography or the 'Vista