Flash stock rom with Odin in DL mode to get 'clean slate', re-root phone & restore nandroid or re-flash custom rom/kernel. If the Odin flash doesn't work, get the 3 part firmware linked in Hopper8's 'Odin troubleshooting' guide in General & flash that.
If it's important enough to cause you grief if it's lost, back it up. No excuses
Trolling for thanks is lame
Does Samsung's auto-brightness implementation crap drive you to self-harm ? A solution !
Failure to search is the leading cause of male impotence on XDA
If you don't know how to recover if things go wrong, what are you doing flashing custom roms ?