+Haven't moved the original music at all, but i did rename my 'Music' folder (on my desktop) to 'Audio' i soon changed it back when i realized music could not be located.+
Renaming the folder is pretty much the same thing as moving the music, as far as itunes is concerned.
After renaming it back, did you restart itunes?
I have the same issue. I was in the process of loading CDs into my library. All of a sudden most songs except the Cd's I loaded today cannot be found. iTunes has been working fine with my library on an external drive until today. I copied the entire library back to my internal drive and pointed iTunes to it with the same result. I rolled back to iTunes 10.1.1 and got the same results. Seems as this is a issue with many, I'm surprised no one has come up with a solution!
Richard, your profile says Mac - this is a windows forum.
However the solution gets posted quite often for Windows - windows will change drive letters on exHDs when other things are plugged into USB ports. If itunes is looking for songs on the F: drive and windows suddenly changes it to G:, itunes gets lost.
The solution is to assign a permanent drive letter to the exHD. In Windows, that means using the Disk Management utility.
Don't panic, it's much easier than it looks!
Sorry if there's a quicker way i'm not aware of, but this is how i did it and it worked perfectly for me.
1. On your PC (I have Vista) search in the start menu the name of a song that DOES have a next to it. Right click it and select "open file location". That should take you to the containing folder, then select all the songs in the folder that your selected song is in ('Limewire Downloads' etc. I used to get my music from all over the place) and then hit copy.
2. Search in the start menu the name of a song that does NOT have a next to it. Select "open file location" once again. This is obviously the folder all of your music is that iTunes can locate and has no problem playing (Mine's in MUSIC > "iTunes folder"). Paste all of the selected songs from the folder of the song that was marked with a to the folder of the playable song.
3. Go back to iTunes and there will still be the songs marked . Don't worry, click on a song then when iTunes says "iTunes cannot locate song" simply "locate song" or whatever the button says. Go to the folder containing all the music you copied into (My MUSIC > "iTunes folder"). Select the specific song and then "Okay". itunes should then ask "would you like to use this process for the other unplayable songs in iTunes library?" or something to that effect. Click "yes".
4. Enjoy stress free music should work perfectly for Vista or any Windows operating system, sorry it's so long.
N.B. If you think you have other music in random folders on your PC that you have currently on iTunes just repeat the process if need be.