“I have an ipod U2 20gb, which has gone corrupted. I don’t have backup of the music in it – can i do anything? The iPod just does not turn on. iTunes says, it has detected an iPod that appears to be corrupt. My Computer option does not recognize the iPod. If it shows as an E drive, under the properties, I see zero bytes of data – I have about 1500 songs.”
This is a common problem that seems to have more to do with a communication error between iTunes and iPod rather than there being something actually wrong with the iPod. A series of troubleshooting steps may be required to identify a solution, although in some cases the solution is to have Apple Care.

One of the first things to do is be sure the battery is fully charged. You may need to leave your iPod plugged in for a couple of hours before attempting to do any additional steps.
The next thing to try is to attempt to reboot your iPod. On most iPods this requires making sure the iPod is not in Hold mode, then holding down the Menu button and center button at the same time until the iPod restarts.
Stage three is to unplug all your USB devices, including your iPod. Shut down your computer and remove the power cord for a few seconds. (Save any important files on your computer before shutting down) Plug the power cord back in and restart. Once your computer is completely booted, open iTunes and reconnect your iPod. In many cases, this resets your USB connections, which frequently solves iPod connection issues.
My next potential solution would be to download and install iPod Access. The software isn’t free, but you can use it for 14-days, which is long enough to test out recovering your iPod. After you install the software, connect your iPod to your PC and see if it can see your iPod. Even when iTunes can’t see your iPod, there are times when iPod Access can.
If none of these steps work, you may have to make a trip to an Apple Store or contact Apple customer support to recover your iPod. If that happens, very likely you will lose any music tracks currently on the iPod.