You can use Apple iTunes to view and listen to audio and video content whether or not you own an iPod. While the iPod makes your library portable, iTunes still lets you purchase content from the iTunes Store, download and import content from other sources and organise your music and video files in several different ways. Upgrading or replacing your computer will require you to transfer your library to the new computer, using a storage device like a memory stick.
Locate the iTunes library by opening iTunes, clicking "Edit" on the menu bar and then clicking "Preferences..." Select the "Advanced" tab and take note of the library file path in the first block in this window.
Insert your memory stick into the appropriate slot on your computer.
Open your operating system's file browser. For Windows XP or earlier, this will be "My Computer." Find the library folder noted in the iTunes preferences.
Select the iTunes library folder. Click and drag it to the drive-letter icon for your memory stick and release it.
"Authorise" the new computer to play purchased content. This can be done using the "Store" menu in iTunes. "Deauthorize" the old computer using the same menu.