Did you resolve your problem?
I have the same issue, and nothing works.
I am computer savy so I did all the steps, twice.
I also tried it on other PCs, and with other cables, as well as other iphones and ipads on my laptop.
I even installed another partition of other windows on same laptop - all work well, except my main windows installation on my main laptop with my new 5s iphone. IT isnt recognized for charging or to be connected to itunes.
When I turn on my laptop, it gets power like the other iphone which is working well.
on windows startup in middle it stops. then when windows are loaded, other iphone is connected and powered and recognizable, but this one neither.
I managed to copy old iphone to new 5s 64GB throgh another laptop, but my music and other stuff are on laptop installation I cant reach.
please help!!!
Mario from Croatia.