Q: how can I find the rest of my download music

Have you deleted or moved/renamed any directories on your computer ? By default your iTunes library is stored under :

• Mac OS X: /Users/username/Music
• Windows XP: \Documents and Settings\username\My Documents\My Music\
• Windows Vista: \Users\username\Music\iTunes
• Windows 7 and Windows 8: \Users\username\My Music\iTunes

Finding lost downloads : http://support.apple.com/kb/TS1408

If you can't find your music on your computer then you could copy it back from your backup of your libary. If you haven't been keeping a backup then you might (depending upon what country that you are in, whether you've changed countries since buying it, and if it's still in your country's store) be able to redownload it via the Purchased link under Quicklinks on the right-hand side of the iTunes store homepage

If music shows there but doesn't have the cloud icon against it for redownloading then do you still have it listed in the Music part of your library ? If you do then try deleting it from there and it should then get the cloud icon in Purchased

(For future info typing all in capitals is considered shouting, and may mean that people are less likely to reply.)