Ipod device detected but not working properly

Hello,
I am having a problem with my ipod not being recognized by my itunes library. I just got a new computer with windows 7 and when i went to plug my ipod in it tells my that my ipod has been detected but the device is not working properly. When i pulled up my devices in the control panel it had a yellow triangle with exclamation point inside of it and it said that it needed troubleshooting and gave a code 21. I have tried to uninstall itunes and reinstall, but has the same outcome. I plugged it back into my old computer and it works fine and my also my ipod shuffle works fine with itunes on my new computer, it seems to be just my ipod and iphone. Please help!