Check your usb cable or try to replace another one.,also check the usb slot of your phone,might corroded likewise and need to clean as well,see if the pins of this connector are well align,you can use magnifying lens to see it closer.clean it using a pin or a dry toothbrush,be sure to take off the battery first to avoid short circuit.also check the usb port of your computer,try to plug it on another slot.
You might need this software to be able to synchronize your phone to your computer
Download this file :
ACTIVE SYNC* After downloading, run and install the application,and then plug your phone using usb cable then wait until drivers are installed and then it will automatically sync the phone on your computer.
Hope this method helps, thank you for visiting FixYa.