Mac Forums

I had a problem with my iTunes, it wouldn't even open. Something about it being corrupted. So, on the advice of a friend I went through steps that I don't even remember (helpful, I know) and removed some kind of music file from the iTunes folder, re downloaded it and it worked. Renamed the music file... something like that. Anyway, now for some reason my songs on my iphone are not on my itunes. I try to sync to my itunes to get my new purchases on my iPhone but it tells me that it will erase all of my music on my iPhone if I try to sync with my iTunes. Same computer I've had for years, so it should let me sync all my stuff, right? Anyone have any idea what's going on? Sorry for the convoluted question, if you have any questions just let me know and I'll specify.