Take a look at this article named iTunes: How to open an alternate iTunes Library file or create a new one found http://support.apple.com/kb/HT1589 to direct iTunes to open the library you copied over.
I would also change the location of the library in the iTunes preferences
iTunes for Mac: Moving your iTunes Media folder
- Open iTunes.
- From the iTunes menu, choose Preferences.
- Click the Advanced button in the Preferences window.
- Click the Change button in the iTunes Media folder location pane.
- In the Change Media Folder Location window that appears, navigate to the location where you would like your new iTunes Media folder to be created.
- Note: By default, your iTunes Media folder is a folder named "iTunes Media" in ~/Music/iTunes/ where the tilde "~" represents your home directory.
Purchased a new PC with Windows 8. Migrated the iTunes library and associated music from the older computer to the new
How did you do this?
All you need to do is copy the entire /Music/iTunes/ folder from old computer to /Music/ on new computer.
Then when you open iTunes on teh new computer, it will be identical to iTunes on the old computer.