Unfortunately the symptoms are not specific enough to identify the cause. Going into recovery and clearing the cache might help. A factory reset is more likely to, but you lose any data that aren't backed up. But nobody can be sure: it might be that there's one specific thing you need to do to fix it, but we don't have enough information to work out what. Or it might be a hardware failure that's not worth the cost of repair. Just the fact that it's rebooting isn't enough to tell.
If there were any other problems before this please tell us, as that might give a clue.