My 8GB Zune was playing fine today, until I hit the "back" button. It restarted, and was playing again. I hit the "down" button to lower the volume and "poof", it shut down and was stuck in the "Zune" loading page. I let the battery die, hoping hooking it to the computer would clear it up, but it just flashed the low battery symbol, then went back to being stuck on the "Zune" loading page. Help!