iTunes is one of the most popular digital music stores and music managers. Your iTunes account is the key to your Apple identity: it quickly connects you to your iTunes and Ping profile, and allows you to re-download iPhone, iPod and iPad apps. You don't need to sign up for a new account with a new computer, just download iTunes and sign in. Any music and video you purchased from iTunes on another computer will not automatically appear on your new computer, however; you need to back it up and copy it to your new hard drive to listen to it.
Turn on your computer and log in. Use a Web browser, such as Internet Explorer or Firefox, to navigate to the iTunes download page.
Click "Download Now." Save the file to your computer desktop and wait for the download to finish. This may take a few minutes.
Double-click the "iTunes Setup" installer file. Click "Next," then "Install." Click "Next," then "Next" again. Click "OK."
Double-click the new iTunes link on your computer desktop.
Click "Store," then "Sign In." Enter your Apple or AOL username and password. You now have access to your purchase history, App Store apps, podcasts and subscriptions.