When you say, "my ipod shuffle won't work," what does not mean exactly? It no longer syncs? It no longer shows up in iTunes at all?
If it still does appear in iTunes when connected, you may want to try doing a Restore in iTunes on the shuffle. The command is on the shuffle's Settings tab, in iTunes when you select the shuffle. This will erase the shuffle, reinstall its software, and set it to default settings.
NOTE: With the latest iTunes, the "sidebar" where iPods are shown is not displayed by default. You can show it by going the View menu (in the Menu Bar) and selecting Show Sidebar.