Universal Eyes: With norton and beta 1 and adware i''ve been able to find the viruses and worms

eh? how do you got them? in work i am admin of 66 windows systems since 4 years - no virus, n worm ... nothing since there. why?
1) strictly always update the OS
2) Using strictly and strong policies (mails and so on)
3) Using NON-IE-Browsers. At the begin it was netscape, now firefox
4) Using an updated antivirus - i recommend antivir.
5) using a combination of a general firewall and personnal firewall (i recommend kerio=
6) prohibiting using danger ports
...

but of course, the most problems are because people are clicking at everything ...