Microsoft's new operating system makes computing more intuitive—and less of a chore—while offering better overall performance.
The first thing you'll notice about Windows 7 is that it looks like Vista. It also works like Vista, in the sense that it has the same plumbing underneath, except for a very welcome graphics upgrade to DX11. However, it works much better than Vista, and most of Vista's annoyances have either been removed, or (mostly) can be changed so the system works the way you like. It takes personalisation to extremes.
See why and how Windows 7 is better than Windows Vista or Windows XP. Here is a detailed features list which you can do or can not do in different versions of Windows. Windows 7 has got some improved and some other brand new features included in it.
[Microsoft Link]