Clicking on the arrow displays the content of the iPod. Grey text when you look at the content and a lock symbol at the bottom of the screen just indicates that the iPod is set to update automatically (sync). If you want to access the iPod directly, delete songs from the iPod, drag songs from iTunes etc. you need to change the update setting to "manually manage songs and videos". Click on the picture of the iPod, to bring up the preference tabs.
By the way something to remember about using an iPod in manual mode is that the "Do Not Disconnect" message will remain on the display until you physically eject the device. So don't panic. In that case use the Safely Remove Hardware icon in the Windows system tray on the desktop and check this link for alternative methods::
Safely Disconnect IPod
