ClamAV is the only other free AV program I know of that has any sort of credibility, although i think there may be one more. I see it most with Linux (see here
), but they also have a Windows version available named ClamWin
. I haven't tried it out, so I don't know what it's like, but as with most GNU/GPL software, it is probably good, and likely won't take up to much memory, although I could be completely wrong there.