Trojan viruses and intrusion attacks

Norton Internet Security is continually finding and quarantining many Trojan viruses and intrusion attacks. Last night I clicked Support and Norton said that my Windows BFE was missing and needed repairing in order for the Norton firewall to work correctly. I followed the instructions and was able to re-establish the BFE and Windows firewall. But Norton is still saying that it is quarantining several Trojans and intrusion attacks. Sounds like I still have viruses on my computer. What do I do?