There are several AV's that do well with trojans. Kaspersky and the various antivirus software using the Kaspersky engines all rate highly in trojan detection. Kaskpersky, at least the v4.5 slows my one year old machine down almost as much as Norton did, but I've never had anything get by either. Kaspersky is one of the top three, along with AVK and F-secure (or F-Prot), both of which use Kaspersky's engine. Norton came with this thing when I bought this box. It left as soon as the 3 month trial expired.