First of all, Vol+ + Home + PW. then wipe user and Cache both.
if not work above procedure, then do this Process. 100% Working.
You need these files.
01. Full Package Firmware (os 2.3.6). S5830iXXKL1_S5830iXXKK5_OXEKK4
02. And Pit file S5830i cooperve_0623.pit
03. now use both volume button holding and connect usb cable for Download mode.
then do as like picture bellow.
05 Best of Luck Friends.