[mkid234]

My 3gs and 4s does not connect to itunes. it does not even show up as a camera and does not show up under the universal bus controllers and also does not say "usb mass storage device". It worked fined one day and couple minutes later i tried to update another phone, it does not show up.My phone chargers when i plug it in.

 

[Laxer]

If it still does not work you may need to launch it in recovery mode...

iPhone 101: How to Put the iPhone Into Recovery Mode | iMore

 

[sobeit]

try rebooting the computer with them plugged in. I had a similar problem and that is what I did.