computer doesn't recognize anti-vir

new here,new to computers so please bear with me. I bought my first ever computer in 04/09. yeah i’m an old guy that just retired and crawled out of my cave. anyhow,I have an h/p pavillion /vista home premium. I bought Norton System WorksStandard edition 12.0. I loaded both parts and registered them. My problem is my computer doesn’t recognize the anti-virus part. In health check it shows I don’t have it but when I run a h/p health check,it comes back okay. What’s up?  lige