i can't put music on my iPhone!?

[Smile =)]

I updated my iTunes so my iPhone would be recognized, but once I plugged it in and tried to drag my music onto my iPhone (on the left sidebar) it wouldn't let me do it. The circle with the line through it thing came up and the songs wouldn't transfer onto my iPhone. I also tried to sync my iPhone with my music, but it deleted my apps and then wouldn't let me click on or play the music once it was in the iPhone library on my computer. I don't know what to do! Please help! thanks