MP3 players: Creative Zen- Sync music, but not found in Media Library

Creative Zen- Sync music, but not found in Media Library

I have a Zen Touch 20GB. I purchased it back in december or january, and it was running fine. I decided to update the firmware so that I could run it with Windows Media Player 10, although I have yet to update WMP back up to 10- So I am running 9. Anywhoo, after updating the firmware, which erases all of the files, I tried to sync all of my music back on the player. The files transfer, the memory goes down, but when I go to play music, nothing is under my media library on the player itself. I have tried to sync everything twice. It's getting quite frustrating. Even the player itself under information shows that the storage of the unit has gone down- so I know the files are there. Why can't I access them? Please help!

PS. I was also wondering why, before I updated the firmware, the player would show up in my computer. Now, it does not.