I recently got infected with the Back Orifice 2000 (bo2k) trojan and Norton AntiVirus 2002's AutoProtect noticed it on my system. I could not clean it so I quarantined it. When I quarantined it, it broke through the quarantine! AutoProtect then notified me that the Norton Quarantine folder (something like C:/Program Files/Quarantine) was infected! It then broke free and started creating havoc on my system. I never knew a trojan could do this.