Mine (30GB old style) did this a few weeks ago. I normally have it plugged in the aux input in my car and listen to it EVERY day driving to work, then plug it into the PC at work all day, then it goes back in the car for the ride home and i never have issues. But the one time I want the thing to work it freezes on me. We took a long roadtrip, about 9-10 hr drive, and after the 3rd hour the zune froze. I made sure to charge it up fully the day b4, but it freaked out and acted like the batt. was dead, got stuck on the loading screen and none of the reset buttons would work (even with charge cable connected). I was quite annoyed because Driving through pennsylvania, there are just about NO radio stations to listen to, unless your a 50 year old hick or you have been locked in a bomb shelter since the early 80's (for some reason all the songs I heard as a kid are still considered "new" when you're in PA, but thats another story)
Anyway I got to NY I tried to connect it to my moms' PC and there was no change. I let it die than tried to restart it, but still nothing. finally I opened the Zune up and disconnected the battery, waited a bit, then reconnected. It works fine now and hasnt done it since.
(BTW the case opens up pretty easily, you just have to pry out the sync cable trim piece which reveals two phillips screws. remove those and then pry the sides of the case apart, and slide the back section up and over the headphone output) i nicked up the plastic a bit on mine but who cares, I was about to toss the thing out the window anyway
