Why wont my phone let me sync songs from my computer when the USB is connected?

[Windows Central Question]

My computer says that my phone is connected to the computer (my phone is a Windows Nokia Lumia 520) The USB is connected from phone to computer.. Why wont it let me sync songs when it says my phone is connected???

 

[xandros9]

Is the phone on and not currently locked by a passcode? (as in, its been put in since plugging it in)