How can I unlock my iPod after replacing the battery?

[I_Wonder]

Help! I am SO frustrated! I recently replaced the battery on my 40GB iPod and now it is locked! I have tried everything I can find online to unlock it, but nothing seems to help. I've tried resetting it (both while plugged in and unplugged), restoring the entire iPod, opening it up and manually toggling the switch(it is not stuck), and last but not least, tapping it on a hard surface.

It comes on when it is attached to my computer/and or plugged in but the padlock remains.

Any advice would be great!

Thanks!