After you move the music files from the original location, in iTunes you will have an exclamation mark before the mane of the file and you will have to locate it.

If you have moved a lot of files the easy way is to recreate a new library and rescan the computers for the music files.

To create a new library:

1. Open iTunes while presing shift key.

2. Click on create libarary

3.  Choose a name for the new folder and click Save

4. In iTunes, under Find music files click Find MP3 and AAC files in my Home folder

If you want to use the default name iTunes, rename iTunes to iTunesold, when you open iTunes program it will create a new iTunes folder, you can move the music files from iTunesold folder to iTunes folder and proceed to step 4.