Well reading though the forums here before posting a topic that's already been posted many times would be a good start. Failing that if you can see Customize load it up and check the settings. It's such a bad design that when you flick through the list of applications to organise them you end up hiding half of them which is why I uninstalled it straight away. If you can't see customise then launch installer and download one of the launcher apps, then start that and use that to start customise. If you cant see customise and installer or even launcher, then SFTP to your ipod and delete the customise app. Reboot your ipod and start again.