Could you provide any more details? Anything that happened to it recently, did it maybe lose power during an update or something?
I have the same problem of this.. It happened recently when I try to unlock my samsung galaxy y ..the notifications appear this "SD card removed unexpectedly" and after that it turns off.. I turned it on and only the "SAMSUNG GALAXY Y GTS5360 " appears and turns off. I try to took the battery off and when i put in on..it just automatically appears the "SAMSUNG GALAXY Y GTS5360 " then off pls help i dnt have any other phone. I'm a student.