Here Available Download Link Samsung GT-S5830i Latest Firmware Flash File. Before flash your device first check your smart phone hardware problem. if your device have any hardware related problem at first you should fix this problem than flash your device.
check your device battery charge make sure your device battery 70% up. if your device battery is empty don't try to flash your call phone. if your device is turn off without complete this flashing process phone will be dead.
also don't forget to backup your all impotent data like photos, videos, images, contact etc. after flashing your phone you can't recovery this data.