iTunes library move
- Make sure that iTunes is closed and not running.
- You will have to copy the library, i.e. iTunes folder to your new desired location.
- Now, start iTunes.
- You go into the settings of iTunes (see image).
- Under the "Advanced" Tab, click to the right of the menu item "iTunes Media folder location" of "Change".
- Now select your new location. To do so, enter the sub-folder "iTunes Media" and not the main folder "iTunes".
- After you have confirmed the path, you can delete the library in the old location.

Menu bar in iTunes
These instructions apply to iTunes 11 on Windows.