undo homegroup

Today I ran into the icon "homegroup" on my pc.
No idea what it was so I tried to delete it but to my surprise that didn't work.
It appears to be non deletable.

I searched for what it was and to my surprise a homegroup only can be activated when actively doing so by going to the control panel>homegroup>etc.

I did non of this!!
I didn't even knew it existed and I certainly don't need it, There's just one pc in my home.

Now, how is it possible for a homegroup to be spontaneously created? and how can I undo it?

 

I just saw that the icon has disappeared from the desktop, as spontaneously as it had appeared.
Problem solved.