main software and file system
you can download them both at the download section
to find out which one you need, turn your phone off, take the battery out, insert it back(do not power on the phone). now download and open setools 2, press the button Identify(right side of the screen). Now you must hold the "C" key on your phone pressed and insert the cable into your phone(providing that the drivers are already installed and usb is in the pc). In the left side of the windows you cand find the information you need to download the main and the fs.
for flashing, there is a step by step guide un this forum(use search)