Reset the iPod:
Turn the Hold switch on, then back to off.
Press and hold the Menu and Select buttons for 10 seconds (until the Apple logo appears).
You may need to repeat the reset several times.
If the reset doesn't help, then put the iPod into forced disk mode.
Put iPod into Disk Mode:
Apple suggests that you ensure your iPod is charged before following the next step. How exactly you check a charge on an iPod screen that is completely white has yet to be revealed. But hey, give it a shot anyway. Plug the iPod into a high-powered USB port, let it sit for 2 hours, then disconnect it. If you have a wall charger, plug in the iPod, then follow these steps while it is still plugged in.
Turn the Hold switch on, then back to off.
Press and hold the Menu and Select buttons until the Apple logo appears
Immediately switch your figures to press and hold the Select and the Play/Pause buttons until "Disk Mode" appears at the top.
For a lot of people, this solves the problem. Connect the iPod to the computer and (assuming it shows up) reset the iPod again to get it out of Disk Mode. If at this point you still have the white screen, restore the iPod using the restore function in iTunes under the Summary tab (this will erase everything on the iPod and put it at factory settings).
Don't disconnect or eject the iPod until the store is totally done. After you think it's done, wait another five minutes.