When you work in the tile-based interface, you
work on one application at a time. If you switch applications in the
tile-based interface, Windows puts the program to sleep. You don’t need
to close an application to open another one in the tile-based interface,
provided you have enough memory in your device. Windows 8 treats the
Desktop as if it were just another the tile-based program.
To switch apps using thumbnails
1. Tap or click the upper-left corner of your screen to see a thumbnail of an open program; click it to open it .
Click an application thumbnail to switch to that application.
2. Tap or click the open thumbnail again to see the next open app, and then click that app to open it.
3. Tap the upper-left corner and drag down, or right-click and drag down and then up again, to show the Switch list . Tap or click the application you want to switch to.
The Switch list allows you to click the program thumbnail you want to switch to.
To switch apps with the Task Switcher
1. Press Alt+Tab to view the Task Switcher .
The Task Switcher is activated by pressing the Alt+Tab keystroke/.
2. Press Tab again until you highlight the application you want to switch to, and then release all pressed keys.
When you have multiple applications open in the sidebar, you can use 
+Tab to move between the programs in the sidebar from top to bottom. 
+Shift +Tab moves you between applications from the bottom to the top.
To switch apps on the Desktop
• Click the application icon on the taskbar.
• If there are two or more open
documents (windows), hover over an icon and click the file thumbnail for
the app you want to select.
Tip
If a program freezes and you can’t switch out
of it, press Ctrl+Shift+Esc to open the Task Manager. You can then use
the Task Manager to close the non-responsive program as well as switch
to another program.
