Hacktool.Rootkit

Hi, I'm new so forgive me if this is the wrong place to post this.

 

Everytime I start my computer Norton finds and blocks Hacktool.Rootkit. I think Norton is doind it's job, but i'd like to know why it's blocking it everytime I get on my computer. My internet connection was very slow a few days ago and I lost my window icons and my computer crashed. Then we had a poweroutage then Norton started saying it finds and blocks Hacktool.Rootkit. Everything else is normal. Hope i've made some sense. Thanks for you time.