Go to the control panel for printers and devices, foreign USB devices.
Does your iPod show iwth yellow alert error?
MTP USB Device (Standard MTP Device) "cannot start. Code 10"
Device Manager, same thing.
The first time you plugged your iPod in, did Windows show "installing device driver" ?
For me, steps I take to work, before plugging in iPod, make sure iTunes is closed.
Then go to Services and click on Restart for all three (Apple Mobile, Bonjour, iPod);
Then launch iTunes followed by attaching the iPod.
It was working normal until I had an error and was led to Printers etc to find the iPod in error
"this device cannot start. Code 10."
Reinstall, even with manaully removing things that the uninstallers for all the Apple programs doesn't catch, doesn't make a difference (for me, multiple times and computers). my "incense burning" step is to just Repair the program in the control panel instead. Apple keeps cached installers of every version and copy on your hard drive (Program Data).
I thnk it hinges on poor device drivers in Windows.
If you are using Windows 7, go to:
Control Panel>Programs>Programs and Features
Look for a program called 'Apple Mobile Device Support'
Right-click on it
Wait until the repair operation is complete, and voila, your problem should be solved, itunes will recognise your iphone/ipod once more. This worked for me.