So I uninstalled iTunes and installed the newest version a few days ago. Today, I tried to put some music on my iPhone but iTunes wouldn't detect my phone. So I went to Administrative tools and went to services and started Apple Mobile Device and iPod service. After that I reopened iTunes and it detected my iPhone. However it detected as a new iPhone and it asked me if I wanted to back it up or set up as a new phone. I chose set up as a new phone. I then tried to drag and drop the MP3's into my iPhone's music but it wouldn't let me, a red circle with a slash appeared when I tried to drop it in. I went to the Summary tab and checked "Manually manage music and videos". I clicked Apply and it said "Your iPhone is synced with another library, you have to erase and sync." Now this is the only computer I've ever used and I never sync my data onto my computer because I don't need to, it's a hassle and I only need my phone data on my phone. How do I fix this? Thanks!