Norton Won't Scan!

I'm usng Norton antivirus professional 2003,and I tried to use it to scan for viruses,It said that I was missing some components,and told me to re-install,and I had reinstalled it for a number of times,but still nothing.I've tried downloading the Norton antivirus 2003,but still the same problem.Both of them I had downloaded it from Kazaa,and I tried downloading from every other user,but still no luck.Does anyone have any idea how to fix the problem?

Get the one from the varifieds it wotks with no problem m8.