after updating itunes it wouldn't find any devices

the new update for itunes on windows 8.1 wont work

i cant syn any iphone i have or ipod it wont even show up

i have one conected but in my computer it is conected and i can get pics of it

help me pleasei have 2 x iphone 5s and 2 x iphone 4 and 2 x ipod touch i need this to work