Galaxy Y is restarting again and again after factory reset.
A hard rest on that device is: Hold and press the Volume up, Home, and Power buttons simultaneously for 10-15 seconds.  

There is a set of visual instructions here: http://visihow.com/Reset_a_Samsung_galaxy_young_gt-s5360_using_two_different_methods if you want to get a sense of what that will entail.