So I recently restarted my computer to factory settings and everything was deleted. My music was also deleted from my iTunes and I wanted to add a few songs today onto my phone but it wants to remove my old songs and sync the new ones. I don't have the old music on my computer anymore and I don't want to download them all again cause it's too many. I think my phone believes that this iTunes isn't the same one since everything is gone. I don't know, How do I fix it?
You should have had a backup of the computer so you could have copied your iTunes library. You are correct in your assumption that the iPhone believes this is a new library because nothing is there. And it really isn't the same since you have reformatted your drive/computer. This hint should help you out.