How do I transfer my iTunes library from a desktop PC to a laptop, neither of which are Apple computers?
All the items in your iTunes library, like music, TV shows and podcasts, are stored in folders on the computer. The iTunes software itself, which is basically a big database program crossed with a media player, displays the items in your library in lists and makes it relatively easy to manage your collection.
To move your library to a new computer, you just need to move your iTunes library folder from the old machine to the new one with a copy of the iTunes software installed. You can do this in several ways depending on how you use iTunes — including transferring all the files over your network with the Home Sharing feature, copying your iTunes folder to an external hard drive or set of DVDs for transport between computers, or transferring content from the iTunes Store with an iPod, iPad or iPhone.
Apple has step-by-step, illustrated instructions for all these moving methods (and others) on its site. If you plan to get rid of the old computer, be sure to deauthorize it for use with your iTunes purchases, as explained here.