Found this thread by searching for 'Fastest Antivirus'!I would like to add to the above about Norton:-I?ve had a laptop for just over 18-months, (online daily) with no protection other than standard Windows XP.I decided it was about time I got some, and a few weeks back I bought Norton System Works 2006 online after their website claimed it would ?Increase the performance of my PC?Well first time I did a virus scan it found nothing ? that?s the good news!But as for improving performance ? that?s a complete joke.Instead of taking 60 seconds to boot up, it was more like 5-minutes.All programs took much longer to load; e.g. Word took up to a minute to start up while Norton did a totally unnecessary virus scan, and the same thing every time I opened a document.System Works is the most garbage piece of software I have ever seen, and within a week I had uninstalled it.To be fair, when I complained to Symantec they did refund my money with no fuss at all.(No compensation for my wasted hours installing & uninstalling though!)So now I?m going to try some of the above suggestions. Nothing can be worse than Norton!