I have a Samsung Galaxy Y mobile. In internet I saw a post that update your Samsung Galaxy Y from 2.3 to 4.0. I tried the steps but I went wrong now my mobile getting rebooted again and again. How can I get my previous version?
If you can enter into Recovery Mode(with Power and Volume Up buttons pressed on startup) try to restore a nandroid backup(if made) or flash a new ROM.
If you can't enter into Recovery Mode you need to reflash a stock ROM using ODIN. You need to choose the Right Stock ROM for your region. See XDA-Developers, it also contains a guide to flash these files with ODIN.
Then you can go on trying to update to ICS or JB.
Thank you all. I got the Solution here