My brother's iPod does the same thing. Usually restarting your computer will help. But like Connor Marie said, wait a couple minutes, or keep plugging and unplugging it. Restarting always helps though if you're looking for the quickest solution. :P
Sometimes mine does that too. I usually just wait a couple minutes, and it comes up, or I unplug it and plug it back in. I'm not sure WHY it does that though.... : \ Apple isn't exactly the most fantastic quality, as I'm sure you know.
yeah ist working fine now hst had to restart the computer !!! thaks 4 the answers u saved my life :)
Glad I could help. :)