Have you tried a hard reset yet? To do this, press and hold both the Select (Center) and Menu buttons together long enough for the Apple logo to appear
Otherwise have you tried connecting the device to your iTunes library yet? If you can successfully connect the device to iTunes you can restore it by clicking the Restore button under the iPod's Summary tab.
It might be necessary to place the iPod into Disk Mode in order for iTunes to see it. Use the instructions in this article to get your iPod into disk mode.