If you have tried all of these ways. then The only thing I can think of id you have an issue the micro usb port on your phone. I would suggest you return to stock unrooted and take your phone into sprint for service. Here is the easiest method for doing this:
[NOTE]Always check your current count state in download mode prior to using triangle away. If what Triangle Away and what is shown in download mode doesn't match, do not proceed.[/NOTE]
You will be will be resetting your phone with an app called triangle away, which has just been updated to support all US versions of the GS3. Click on the link below to download triangle away.
Click here To download
Triangle Away
Please thank
Chainfiire for developing this great app.
Installation instructions and how to use it are in QBKING77's Video Below.
When you've completed the above steps.
1. Download the "easy Return To Stock" file.
2. Place it on the root of your external or internal sdcard.
3. Boot into custom recovery
4. wipe cache partition, wipe dalvik and wipe data/factory reset
5. install zip from sdcard
6. choose zip from sdcard or external sdcard (depending on where you placed it.)
7 select "LI3_STOCK_COMPLETE.zip"
8. confirm selection
When complete reboot. If the phone does not boot. Turn it off by pulling the battery. Boot into stock recovery and choose factory reset. When complete you should be good to go. If returning your phone to sprint, remove your sd card and delete any files from your internal sd that would indicate you were rooted. such as roms, cwm back ups, mods. I always put these files on my external sd so that removing the external sd card also removes any evidence of root.
Easy Return To Stock