How Do I Fix My 30 GB Zune?

So i have a 30gb zune and i just redid everything on my computer and had to re-download the zune software.
So after i downloaded it i plugged in my zune and it said i needed to upgrade it. So i did. Well ever since i upgraded it, it will do the zune loading screen and then shuts off and re-does it. Sometimes when i plug it in it will load about 8 times and then work but when i unplug it, it just shuts off.
SO what do i do so it will work?
i have tried reseting it.
deleting everything off it
download the software again.
PLEASE HELP
And
Thanks to all the people that try =)