Samsung Galaxy S3 Won't recognize USB When i got my gs3 i plugged it into my computer (Win 7) and drivers installed automatically. everything was perfectly fine i was able to access both sd and phone from my computer. i took it to activation with clear talk and it didn't recognize usb.
I have reinstalled proper drivers from samsung web page. i have also tried kies. kies wont accept it.
I have tried it on linux and didn't work.
Both computers recognize phone but phone wont recognize computers.
The thing is i won't get the option of mtp or ptp on the drop down notification menu.
this is not a matter of drivers or usb debugging.
i have tried to remove battery for 1 min and reset it.
any ideas how to fix?
After frustrating research i found the solution. the guy who flashed my phone from us cellular to clear talk messed up. 
soulution
Open Dialer enter *#22745927
When Enable/Disable Menu comes up tap "Hidden Menu Disabled"
Select "Enable" on Popup
Press Home button
Open Dialer
Dial **87284
When PhoneUtil Opens Select PDA
Tap Qualacomm USB Setting
Select DM+Modem+ADB
Tap OK
(Remember after flashing to return and put phone back to MTP+ADB)
All props go to this page
http://forum.xda-developers.com/showthread.php?t=2270191 
there is other devices listed there as well.