I have blinking Do Not Disconnect HELP

If it's not mounting on the computer or there's no way to eject it from iTunes, your only choice is to disconnect the cable from your PC. This will not "damage" the Hard Drive on your iPod, but only the File System, which can be reformatted using the iPod Software that came with it.

See: Resetting iPod if it appears frozen or doesn't respond

One thing you can do as well is reset the nano while it is still plugged into the cable.

To reset press the menu button and the center click button simultaneously for ~5 seconds until the apple logo appears. Afterward the nano's main menu should display (no more do not disconnect message). Now you can disconnect.

Joan,

When do you get this message?
You are supposed to get the message when the Nano is plugged in (plugged into the USB or through the dock).

That is because the Nano is trying to charge itself or udpating from iTunes. If you have iTunes, then open it up, and eject the Nano from there(after update is complete). The "Do no disconnect" message will disappear. Then you can disconnect your ipod.

If you do not have iTunes, then you should get it NOW! Download and install it from the website.

Typically, even if you do disconnect, nothing too bad will happen. Some songs files MIGHT get corrupted, but that's about it. I actually used my IPOD withuot any iTunes or IPOD drivers. Then it works just like a USB flash drive:)
I still recommened using iTunes though. It's the safe way.

If you are getting this message when you ipod is not connected to anything, then it's an issue you want to contact Apple about.
Hope that helps.

I have the same problem, with my nano 2GB!!!
I tried a reset while pressing menu and center..Its still blinking. Is it broken? or is the battery charging?

I just tried to reset the manufacture settings...Uptaded...still it does the same thing

Dumb question but is it still mounted on iTunes?
Also is it mounted on the desktop (finder).

If yes for either of these, click the triangular "eject" icon next to the nano. If the nano is no longer mounted, the display should go to charging (blinking green battery logo with lightening bolt, or solid battery with electrical plug (fully charged)).

If you cannot "reset" it, even when connected to a Mac/PC, then your best bet is to wait until the battery fully drains and then "reset" it. If that doesn't do the trick, send it in for service