Q: updated to new version of Itunes and now our Ipods are not recognized.

We have Ipod Nanos and have had no trouble until last night. We updated our ITunes to the latest version and now it says "an Ipod had been detected but ITunes doesn't recognize it". Then it says if the problem persists to uninstall and reinstall ITunes. We have two questions. Why are our ipods not recognized now and do we really have to now uninstall and reinstall ITunes? Also, if that is true, will we lose our playlists in ITunes when we uninstall and reinstall? We have already done other troubleshooting tips such as restart the computer, making sure our computer has done it's updates, etc.