Might be an issue with some sort of software that's keeping it in a loop?
You could try turning it on in safe-mode. Each phone has it's own way of initiating this. This link is for a samsung galaxy ace I. It might be the same for a ace II.
http://forum.xda-developers.com/showthread.php?t=1090072
Once you're in safe mode, I'd try to clear out any apps you think could be causing an issue (any apps downloaded right before this happened, app that has crashed a lot before, etc)