Instructions
Double-click the "World of Warcraft" icon on your desktop to bring up the game launcher. If you don't have an icon on your desktop, click the "Start" button and type "World of Warcraft" into the search field. Then click the "World of Warcraft" item that appears under the Programs heading. The launcher window will appear on the screen.
Wait for the launcher to download any required patches to the game. You will see a progress bar at the bottom of the window. Once the bar reaches into the orange area, the "Play" button will light up and you can play the game. For better in-game performance, wait until the progress bar finishes moving across the screen. Click the "Play" button to launch the game.
Enter your Battle.net account name into the first field on the screen and your Battle.net password into the second field. Click "Login" to continue.
Select a character from the list of characters on the screen. To change servers, click the "Change Realm" button at the top of the list, then click the server that holds the character you want to use. Once you have selected your desired character, click "Enter World" to log into "World of Warcraft."