Clip+ Music folder issues

I purchased a new 4GB Clip+ yesterday.  When I drag and drop music folders from my PC running Win 7 to the Clip, it lumps all the songs into a folder labeled “Unknown”.   If I look at the files in the Clip using Windows Explorer, each file is shown separately as planned.  The folders are all titled with the artist and album name.    If I look at the Clip using WMP, it shows one Unknown folder with all the songs from the various albums arranged alphabetically.  Great if you want to listen in shuffle play all the time but awful if you’d just like to play all the songs by one artist on one album.  This is my first MP3 player and I didn’t expect things to be this difficult.  Any help is appreciated.

http://kb.sandisk.com/app/answers/detail/a_id/115/kw/unknown/r_id/101834

Are the ID3 tags (metadata embedded into music/podcast/audiobook files, identifying the files’ artist, album, title, genre, year, and other fields of information) for the files filled in?  As a general matter, the Clip organizes and shows its music, for you to navigate by, using the ID3 tags.  A major exception is the Folders listing at the bottom of the Music category, under which you can navigate between your folders and files via the folder and file names. 

A good ID3 tagging software:  MP3Tag, Internet freeware.  And CD rippers often will fill this information in automatically when you rip the CD, gathering the ID3 tag information from an Internet database (and generally allowing you to edit that information, if you would like). 

Thanks.  I wasn’t familiar with ID3 tags.  From what I’ve read now from your links and info, I’m sure that will cure the problem.