The following info is to be used at your own risk! But it is an easy repair. unplug your zune from the pc first!!
1.go to the link below to learn how to open and remove battery. (only use the firt 2 steps to open the zune then just unclip the battery (see pics) then reclip battery test that zune come on and reverse steps to close zune.) DO NOT PLUG ZUNE IN AT THIS TIME!!!!!!!!
2. change the date on your PC to jan 1 2009
3. done! sync your zune now. the zune software does not support the Feb 26th so the software killed your Zune at midnight last night ( it is jan1 to the zune) just change the date in your pc back to the first again tomorrow.
As far as i can tell there will be no other way to fix this issue w/o sending teh zuns back to have repairs because they will not sync. If you let the battery die and then chang the date it may work the same but thats not good for the zune and it is likly that all of your files will be deleted.
Hope this helps every body
http://www.rapidrepair.com/guides/zune/zuneassemblyguide.htm