My iPod Touch is set to manual sync--I control what songs sync rather than allowing it to be done automatically. It's working brilliantly on the first computer I plugged it into (a Blackbook approximately 10 months old) but not so much with the desktop (24" iMac approximately 1 month old). I can't get it to show up on the desktop of the iMac even though it makes the little noise that acknowledges it's been plugged in. What am I doing wrong? This is hardly my first iPod, so I'm feeling rather confused.