Norton Internet Security isn't designed to identify or stop spyware from installing. Spyware/malware are not considered viruses and therefore they frequently slip by your defenses undetected. If you run ad-aware or spybot S&D (or both) on a weekly basis .... updating before each use, you'll be able to keep your system running fairly smoothly. Don't discount Norton .... it does its intended job adequately. (Its not the best, but its still one of the best.) You simply need to add an extra layer of defense. Ad-aware and/or Spybot helps there. Consider downloading and installing Java Cool's SpywareBlaster. Its freeware and keeps malware/adware from installing in the first place.