Kies is your best bet.
To get it to work, try this: *This process will wipe your internal sd card*
1. Turn off phone, pull battery and write down serial number.
2. Start Kies and go to tools, firmware update.
3. When prompted enter model number ("SGH-T989", case sensitive, no quotes).
4. When prompted enter serial number.
5. All Windows from this point on will tell you what to do. Just follow them and you'll be ok.
6. Make sure you use a reliable usb cable and don't move your phone once plugged in unless you absolutely have to.
Remember to back up your internal sd card before beginning or you will lose everything on it.
This has worked for me every time I've tried it because it enters an emergency recovery mode. It's slow, but it brings your phone up to the latest firmware available, and it's very thorough (also, slow).
If this doesn't work then Odin is your next bet but that's a very powerful tool that should give people pause before blindly using it.