I had a new shuffle. Tried to charge it for 24 hours ahead of connecting and once I did connect it crashed iTunes. I sent it back and got a replacement. Same thing happened. I uninstalled iTunes and reinstalled and it worked...once. Next time I plugged in the shuffle it froze again.
Do you have the latest version of iTunes installed, which is currently 10.6.3?
Your profile info says you use Windows XP. The system requirements for the latest iTunes says Windows XP Service Pack 2 or later. However, the tech specs for the 4th gen shuffle
says system requirements are Windows XP Home or Professional (SP3) or later. Does your computer meet that requirement for Windows? If this is an older computer, does it have USB 2.0? Have you tried it on more than one USB port, which is directly ON the computer (not on a USB hub)?