It began with the moment when i was exchanging files. I removed USB & my phone hung. Then I tried to Reboot. It took lot of time, I hold on power key for 10 seconds. After then NO REBOOT & NO RECOVERY MODE but Download mode was working. I plugged in USB again, now recovery mode worked & I found my Sd-card corrupted. I flashed different ROM from my friend's backup. My phone successfully reached to homescreen. Further, I again reboot my phone without USB, again phone doesn't boot. I plugin USB & now Recovery mode works & finally flashed another ROM. The biggest problem is "On every reboot, I need USB plugin" which is very painful. Battery is also working fine. Your reply is highly appreciated.