I'm running Norton A/V & Firewall, I just ran a system scan and norton found 4 files infected with trojans, I run live update regularly so my question is how do these files get through or where do they come from?

I connected to broadband and leave the PC running most of the time.

A very good question Beerkite. And the reason why I do not run NAV or Firewall anymore ;)

The best combo I've used would be F-Secure (3 seperate scanning engines combined) & Sygate Pro. I used to get a lot of viruses from web pages running NAV, now I get none. I also have found PC-Cillin 2002 to be very good.