no iphone recognised in windows newest itune update

i updated itunes on my laptop to the newest version and everything was going well, nothing was lost except when i came to change things around on my iphone 4 16gb. i connected it to the laptop via the cable and the pc recognises the phone through "my computer" but when itunes is open no icon appears.

i have deleted and reinstalled the program, followed itunes help prompts (checking, changing the apple mobile device) still to no avail. any ideas as i would like to change my music around.