First, how exactly did you do this move? Many people do it the wrong way.
The right way (for most):
iTunes: How to move [or copy] your music [library] to a new computer [or another drive] - http://support.apple.com/kb/HT4527
Quick answer if you use iTunes' default preferences settings: Copy the entire iTunes folder (and in doing so all its subfolders and files) intact to the other drive. Open iTunes and immediately hold down the Option (alt) key (shift on Windows), then guide it to the new location of the library.
The wrong way (for most):
Do not confuse moving your whole folder and library with moving just media files as in
iTunes for Mac: Moving your iTunes Media folder - http://support.apple.com/kb/HT1449
If you are positive you are happy with what you did, drag the iTunes folder in your Music folder to the trash and empty the trash. I would still make sure you backed up your computer first just in case you were wrong about being positive.
I just moved the media library. I went to preferences under advanced I went under Itunes media folder location and i moved that to my exterenal hard drive. I clicked the two boxes under that, made a new folder and all the stuff did go over. I followed this link on Cnet.
Everything is over on the external drive but before I mess this up I was hoping someone could help me.
Sorry but I can't play that link with my computer. If that link tells you to move your library by changing preferences then that link isn't really telling you how to move your whole library, and is titled incorrectly. Your library is more than just media files, and media's all you moved to the external. Yes, you could just delete those from your internal drive but don't delete the other critical library files or you really will break your iTunes collection.
What are the iTunes library files? - http://support.apple.com/kb/HT1660
More on iTunes library files and what they do - http://en.wikipedia.org/wiki/ITunes#Media_management
What are all those iTunes files? - http://www.macworld.com/article/139974/2009/04/itunes_files.html
iTunes 9 [and later]: Understanding iTunes Media Organization - http://support.apple.com/kb/ht3847
Again, make a backup of your computer first. If you don't have a backup of all your files (those on the external too) in at least two locations then worry about losing files in this situation is only a starter. You could start your computer tomorrow and find it is all gone, 100%.