Sounds like it may be stuck in a "boot loop" A few factors can cause this. A bad, incomplete, or corrupt file was downloaded to the device. Some downloads that are executed by the device can get corrupted. That's why some devs recommend using a computer to download and put the file on the device. Whether it be a simple paste to the internal or external SD, or using ADB's command line, or Odin, or Hemitall's tools.
Another factor can be an unclean flash. Some rooting processes require a full device wipe. Data, caches, folders, etc... can retain info that was necessary for the unrooted device. This old info can contaminate the new info and cause problems. Hope this helps and always make a back up of the device before tinkering around with the files.