I just recently reformated my computer and it is running great! Right now, I am using MSE, and I love it! Practically no resource use, it's quiet, and from what I heard, a very good AV. However, my ISP is offering Norton 360 v4 for free, and I am wondering if I should use that. The only thing I am hesitant about is the resource usage. I used Norton on my old setup and sometimes it would slow my cpu down to a crawl. I have seen other threads on the forum saying that people have installed a paid AV over MSE, and found all sorts of bad things that weren't found before. Is it worth it to switch? (Also consider, my old setup had a bunch of old bloatware on it from Dell, and I never did a full reinstall when I upgraded from Vista to 7, I just used the Upgrade option.) Any experience from Norton?