norton keeps finding comet curser over and over.

Norton keeps finding Comet Curser up to 6 times a day keeps asking me to restart to fix it.  Some days I am only on FBook but I scan FB with Norton and it says its clean.  could it be hiding on my puter,  can I manually hunt it down and delete the files.  This driving me nuts and slowing down things so much i want to throw it out the window.  Should"t norton be fixing this for good or stopping it before it gets into my computer.  very frustrated, thanx for any help/advice in advance.