Automatic Norton 360 update 2015?

Hi, first time thread.

I just downloaded latest iOS update and for some reason Norton 360 started downloading what I presume is an upgrade. I do not know why it didn't ask me automatically. It was taking forever so I cancelled it and now whenever I turn my PC back on, it begins to install itself. (Internet explorer btw)

So I'm letting it go this morning and now it says ERROR:8506, 421 and is attempting to autofix.

Help! What do I do?

Thanks