itunes library on NAS upgrading computers don't want to lose music added to library via CDs help

Hello all,

I'm upgrading from an old Win XP machine to a Windows 8 machine. Complete iTunes library has already been transferred to a network drive (NAS) and is accessible to both machines via Home Sharing. I want to remove the XP machine from the mix but I'm afraid I will no longer be able to access any music that was added to my library from CDs and not the iTunes Store. What can I do to ensure I can acces the entire library and begin to sync my iPods, iPhones, etc. via the Windows 8 machine (after removing the old XP machine) - exactly like I did before. Somebody help a brother out here... thanks!