iTunes won't recognize iPhone

See here,

iPhone, iPad, or iPod touch not appearing in iTunes

Device Not Recognised

For PC

http://support.apple.com/kb/TS1538

http://support.apple.com/kb/TS1567

Worked with me. Apple mobil device was off, i just start it.

For a windows 8 computer my solution after 2 days of forums and no viable answer (as i refused to reinstall iTunes) was this:

"Action Center" ( control panel>system and security>action center )

on the bottom left hand side of the screen it will say "Windows Program Compatibility Troubleshooter"

--click on that and select iTunes. when prompted, select the recommended settings. phone recognized.

hopefully helpful to someone.

(iphone 4, windows 8.1)