Just thought I would throw this out there, I came across a very effective anti-virus system which uses a very small amount of system resources.
It is called NOD32, it is inexpensive, easy to set up, and essentially once you've installed it you never have to worry about it again. It self-updates about every 3 hours with new definitions and the program will update itself as well if you allow it.
Works great with scanning emails from outlook, internet sites, msdocuments, and files which you download or are already existing on your system. And I believe the only thing which has to be set up is the email scanner.
I used to use Norton and Mcafee, and as long as eset is around I will keep it like that.
http://www.eset.com/
-gc
