One of the probelms of AV software is that it takes some of the resources to work - hence a slow-down. You can't have it both ways, and protection is a small price to pay for speed. So far as the rest is concerned, I have found that, when (rarely) and systemworks install goes wrong, there's hell to pay, which is why I always mirror my HD first and can go back and try again; also, if there are any problems already with the OS, this will exacerbate them. Systemworks need a decent OS installation for optimal performance. Also, if you have already installed Systemworks, and try to install over-the-top, expect problems. Far safer to uninstall, delete all Norton folders wherever you find them and then re-install afresh.