New User PR4100 NAS - Need AntiVirus Suggestions

I am new to the whole NAS World, I just purchased a brand new PR4100 32t system. I issues is I am wondering about Antivirus, Hackware and things of this Nature. I Wanted to make sure my NAS is protected. Can you guys suggests a good program to run on the system and keep it clean and free of virus, maleware etc.

You NAS can accept apps from WD (read manual about how to add apps) One app is called Anti virus Essentials or some such name. Just install that app. If you have not spent time with the complete manual, you need to do so asap.