use the f5 key to refresh,
hmm... or this:
ormatting a device may not remove the device category from your library
If you format a device, either in My Computer or by clicking the Format storage media button in the Items to Sync pane (the left side of Sync), all data is erased from the device. However, if a partnership existed between the Player and the formatted device, the device category may remain in the Contents pane in your library. The device category is created in the Contents pane when you synchronize content to a device for the first time. The category name is the same as the device name and the subcategories are the playlists that you selected to be synchronized.
If you connect the formatted device to your computer at a later time, Windows Media Player starts the Device Setup Wizard, which helps you set up automatic or manual synchronization between the Player and the device. A new device category will be created in the Contents pane when you synchronize content to the device under this new partnership. If duplicate device category names appear in the Contents pane, either rename the device or delete the old device category.
To rename the device, do the following:
On the Tools menu, click Options.
On the Devices tab, click the portable device in the Devices list, and then click Properties.
On the Synchronize tab, in the Device name box, enter a new name for the device.
Refresh the Contents pane by clicking another feature tab in the Player (such as Now Playing), and then clicking Library.
The new device name category is displayed in the Contents pane.
To delete a device name category, do the following:
In the Contents pane, right-click the device name category that you want to delete, and then click Delete.