1. Download zip file from HERE.
2.Unpack it with 7zip, winrar, winzip etc.
3.Open it ROOT V790.
4.This gona show you on your desktop:
5.Now connect your phone with your PC and make sure that USB DEBUGING is turned on!
6.Now press any key and wait to complete the process.
Warning: Do not disconnect your phone from the usb cable until the process end!!!
Good luck!