How do I delete and then re install minecraft

If it is installed, probably.

Try deleting it entirely, then go to the start menu and type in %appdata% and click on roaming, then delete the .minecraft folder. Check if java is up to date. Check if your operating system is up to date. Try again.

If you are talking about Herobrine in Minecraft, you can't. He isn't real. Well in vanilla minecraft at least. He is a mod though. Assuming you know how to install Minecraft Forge and how to install mods with it, the link is at the end of this answer. But if not, you could always google "how to install minecraft forge" and "how to install mods on minecraft forge" Anyways here is the link:
Herobrine Mod Minecraft Mods

Hello, Here is the help you need with updating: How to Update Minecraft

Try deleting and re installing. As long as your download withthe same account as you bought it with it will be free because you have already bought it. When you re install it should download the latest version...

go to minecraft.net
login to your account
go to the profile tab at the top of the page
scroll down to ...how you look in game(or something like that)
click add file button... and add the file that you want to look like

I recommend a reinstall of any mods you have. I've only ever had Minecraft crash from making a 15x15x15 cube of TNT and lighting it...

Depending if you have your own minecraft server and a cracked version of minecraft you should delete everything and reinstall to get proper version ect..