Iphone 6s cannot connect to iTune
I have recently bought iphone from market but iphone is not able connect to my itunes (Windows 7) even under iphone setting i cannot configure my account sign in button is disabled under icloud and itune setting options. Also i cannot login to Find my iphone option. Iphone is connecting to usb mode , am able to see all files through usb drive and its charging also, I can make calls, use internet on the phone.
Although i have other iphone which is connecting to my windows iphone and working perfectly.
Please advise the solution.