What is the new Start Screen with Windows 8?
The new interface is the app-driven new Start screen that
has replaced the Start menu. Instead of pulling up a Start
menu, simply move to the lower-left corner of the screen
and tap/click to open the Start page.
You can also always use the Windows key on the keyboard as well.
Links are provided as tiles on the Start screen; apps that provide
updated information are called “live tiles.” Any apps or
programs ran in Start will be full-screen apps.