You have not understood what he has told you.
What the poster is saying is when you install Norton it disables all other virus protection and other protection packages available in the Windows OS. That is normal for installing virus protection systems and it offers you the option of wether to disable or not as I remember.
What you are missing is when the poster didn't pay for Norton anymore all virus protection including Windows OS was left disabled and the poster was not informed of this nor were they aware that their entire system was left vulnerable.
There are a few good virus protection systems available today.
