Keyboard shortcuts of Windows 8

By making the interface more touch-friendly,Microsoft has added a few keyboard shortcuts that mostly make the windows 8 navigation more easily.
Alt-F4 —  This will close  applications .
Windows Key-I — This pops up the new system tray, which slides in from the right. If  hit the Space or Enter key , the  control panel opens. If  hit  Enter key again windows8 shut down the computer.

Windows Key — using this key  popping up the Start Screen for multi-monitor setup is actually more comfortable and an excellent way to check  mail, instant messages, and so on. Tapping Windows Key again hides the Start Screen and returns to the previous app . If  start typing the name of an app from the Start Screen, Windows will automatically start looking for it (just like Windows 7).
Windows Key-F — If specifically want to search through files, rather than apps, use this shortcut key..
Windows Key-W searches for settings.
Windows Key-C — Opens the  Charms menu  and then use the arrow keys to navigate. 

Alt-Tab —  switches through Desktop and  applications
Windows-Tab — This cycles through the Metro apps.
Windows Key-Z — In a Metro app, this opens the App Bar (i.e. the app’s menu).
Windows-Page Up — This switches which screen the Metro interface (i.e. the Start Screen and any Metro apps) appears on. This is only useful if you have a multi-monitor setup.
These are the main shortcuts and many Windows 7 shortcuts still work  too in windows8  but with slightly different functionality.