The Start button which used to be in the lower left corner of the desktop is gone. Microsoft intends you to use the Start screen instead. You can display a modified Start menu by moving your mouse to the lower left corner of the desktop and right clicking on the Start screen icon that appears.
You can use your mouse to navigate Windows 8 even though it was created primarily for finger swipes on tablets and touch screens.
There is still a desktop. To get to it from the start screen either tap/click on the tile for the desktop or use the keyboard command Windows + D.
The Start screen, not your desktop, appears when you start your computer. The Start screen consists of live tiles, little rectangles representing apps, programs, folders, websites and contacts. If you set up a Microsoft account, these tiles will show real-time data, such as Twitter and Facebook feeds. Start an app and it runs at full screen. Start a program and it opens in the desktop.
You can search for an app or program by typing anywhere on the Start screen. The search pane opens on the right.
You do not need a Microsoft account to use Windows 8. However, if you set up an account (or use your Hotmail, SkyDrive or Xbox Live account) your data, settings and favorites will be synced across different Windows 8 devices. You do need an account to download apps from the Microsoft app store.
In either the Start screen or desktop, swipe to the right or move your mouse to the upper right or lower right corners of your screen and the Charms bar appears The Charms bar has shortcuts to Search, Share, the Start screen (when you are on the Desktop), Devices and Settings. Note that Settings shows only the settings for the app or program you currently are using.
In either the Start screen or desktop, swipe to the left or move your mouse to the upper left or lower left corners of your screen and the Switcher appears. The Switcher shows you what apps are open and allows you to easily switch among apps.
The windows on the desktop are flat looking and no longer transparent as they were in Windows 7. Many now use ribbons. Windows Explorer is now called File Explorer.
Windows 8 comes with two versions of Internet Explorer 10. The IE10 launched from the Start screen is more touch friendly and very different from the IE10 launched from the desktop. See 12 Essential Tips for Using IE 10 with Windows 8.
To turn off your computer or put it in sleep mode, open the Charms bar, tap/click Settings and tap/click the Power icon.