iphone4 not recognized

Just upgraded itunes (Win7x64 in bootcamp) to10.5.1, and now itunes wont recognize my iPhone4 when plugged into the usb port. Tried it with home sharing ON and OFF, tried various restarts/repower/etc.

everything else working (itunes store, playlists, etc). single computer. nothing fancy. iphone4 still on last releast (not the latest one). no cloud used/wanted.

anybody know where to get an answer or fix? (i searched around but couldnt find an answer).

tx, g