Trojan Horse

[ukkid76]

Can someone please tell me what a Trojan Horse is (without going into to much detail) since I installed Norton Anitvirus it has alerted me that a Trojan horse (on many occasions) has tried to enter my computer my antivirus has tracked the ip address of the individual computer hackers to various parts of the world. My antivirus has also detected and deleted two pretty serious email various'es within the last two months, So apart from my question I would advise anyone without an antivirus installed on his or her computer to get one A S A P.

[Cactus]

A Trojan Horse is something that appears harmless at first, but once you have let it inside your city (or your PC in this case) it turns out to be deadly. The term comes from a wooden horse that was full of soldiers. It was meant to resemble a gift, but once let inside the city walls the soldiers burst out and started a battle. In PC terms, a Trojan Horse can be an email attachment that appears to be fun (a screensaver or document) but when you run it, it does something malicious like wiping your hard drive, or allowing a hacker remote access to your PC.

[ukkid76]

I know what a Trogan Horse is in biblical terms what I don't know is how can it attack your computer when the computer is sitting idle (obviously online) but not through email or any other obvious source my antivirus will just announce that it has blocked an attack!! Ukkid76