My apple iPod shuffle appears in Windows but not in iTunes
Here's how I fixed it:
I downloaded iTunes & Quicktime.
I then uninstalled all the Apple applications (iTunes, Quicktime, MobileMe, Bonjiour, Updates, etc.).
I had to delete the files in the iTunes folder (iTunes Library.itl, iTunes Library Extras.itdb, iTunes Library Genius.itdb, and iTunes Music Library.xml). I don't know if I needed to delete all of them, but I know that the the iTunes Library.itl file is definitely a problem. When I upgraded to 8.2, it updated this file and essentially forced me to delete it and rebuild my music library. This is where my files were located:
Also, remember to reboot your PC after all of the uninstalls. I also reset my iPod Touch (not a restore, as the above helped me avoid this, so I did not loose the data on the iPod Touch... though I did have to rebuild the music library.
It was a pain, but certainly worth it to hook up my iPod Touch and have instant connectivity. I don't think I forgot anything, but these are the key things.
One last bit of advice... back up all of your data before you begin, so you can restore the data and music and data.