I use Norton, I havn't had any problems with it and I've never had a Virus infect my computer. To lower CPU usage just lower the Auto-Protect bloodhound level to Lowest and make sure to do a Manual scan atleast once a week, I use Norton Utilities 2003 and it does an autocheckup every friday night about 9pm... but you can schedual it for whenever. But I like Norton a lot, has always worked for me and I've never had any problems. Plus, I do computer repair and do a lot of virus removal for people, works like a champ for me with the latest virus definitions.