Sanda,
The virus software is not what permitted the hacker to access your system. There is a reason that Norton is the most highly rated Anti Virus in most of the computing magazines and trades.
The one thing I would suggest is to get the latest version (2003) and set it to check daily for virus updates (if you happen to have an always connected system).
My Norton traps, on average, at least three virus infected emails per week.
I also use BlackIce as my firewall software. On a daily basis there are at least 200 attempts to probe my system ports according to the log of blocked attacks. The nice thing about BlackIce is that it also tracks IP information and I have been able to email several college MIS departments and provide them with the IP addresses of the persons attempting to hack my system. They have all been very cooperative and communicative when I send them the tracking information. The funny thing is, the hacking attempts from that particular IP or university always stop, shortly thereafter.
Here is the link if you are interested:
http://www.iss.net/products_services...protect_pc.php
Hope this helps!
Randy