my itunes does not recognize my iphone so that I can sync music, apps etc

I had the same problem. iTunes would not register my wife's phone as a device. My phone was just fine. So here is how I fixed her problem after exhausting all the apple support tips. First thing I did was go to apple.com and saved the newest iTunes software to the desk top (do not install yet). Then I went into control pannel to uninstall software. Uninstall the following....Apple Application Support, Apple Mobile Device Support, Apple software update, Bonjour, and then finally uninstall iTunes. Then reboot your system, once reboot is complete go to your desktop and install the newest iTunes that you saved earlier. This worked like a charm...let me know if it helps.