New iTunes won't recognize my iPhone 6s?

I just downloaded the new iTunes last night and spent 3 hours trying to find where my iPhone was. I turned my laptop and phone off multiple times and tried plugging different cords in. It always makes the beeping sound and asks me "Is it ok to transfer photos to this computer?" Every time I plug it back in.

  • Will iTunes recognize my iPhone 5 from a iPhone 4 adapter? I want to know if that iPhone 4 to iPhone 5 adapter will work when I go to plug it into my computer to put songs only phone?
  • Why won't my new computer recognize that my iPhone is plugged in? I recently got a new computer, but all of my information for my iPhone is on my old computer. When I plug up my iPhone to my computer, it doesn't register that it is plugged in. Nothing is wrong with my charger and nothing is wrong with my computer. I don't know what to do to get my information from my iPhone onto my new computer and to my iTunes.
  • Why won't my iTunes recognize my iPhone 5c anymore? My iTunes used to always recognize my iPhone, even my laptop right away had something pop up for it when I plugged it in. My brother recently got a new iPhone so he signed into his iTunes and ever since nothing happens when I plug my phone in besides charge it, same for my brother. Is it because he signed in or also because I just updated iTunes? I've tried restarting both my iPhone and laptop.
  • My pc won't recognize my new iPhone 5? I just bought a new phone the other day, and after fully charging(so the USB cable works) it I wanted to sync it to my iTunes library (I also used to own an iPod which my computer recognizes), but my phone didn't respond to being plugged into the computer (not charging, not connecting to iTunes). I tried updating iTunes and rebooting both the computer and the phone. What else could I do?