Sound only works in WMP

I just built a new PC with Windows XP professional. The mobo has 5.1 onboard ALC888 audio. I have a new 5.1 Logitech X-540. I have the newest sound drivers (released February).

All speakers work when playing music from Windows Media Player 9, but there’s no sound anywhere else (no Windows startup sound, no sound from Youtube, etc…). In addition, my sound control panel has so many things grayed out:

Any ideas?