System defender virus

Hi I have a virus on my lap top called system defender it has stopped me getting on Internet and acts like a anti virus package saying it has found loads of issues and then tries to get you to buy it I have run my norton anti virus disc but on a scan it doesn’t seem to locate it Does anyone know how I can get rid of it Thanks Richard

Hi I have a virus on my lap top called system defender it has stopped me getting on Internet and acts like a anti virus package saying it has found loads of issues and then tries to get you to buy it I have run my norton anti virus disc but on a scan it doesn’t seem to locate it Does anyone know how I can get rid of it Thanks Richard