One of the worst internet security products I've tried is Trend Micro's - PC-Cillian Internet Security 2007. My problem with this product began when I noticed webpages taking longer than usual to load. When I launched the task manager to find out why, I was introduced to a nasty little process called PcScnSrv.exe. I was literally shocked at how much processor and memory this thing was using. Upon the launch of virtually anything, PcScnSrv.exe would go totally off the charts.
I queried a search for PcScnSrv.exe and found a veritable army of disgruntled users. Despite a voluminous amount of testimonials and alleged fixes, I found nothing of use. PcScnSrv.exe cannot be disabled without crippling the product. About.com recommended 'removing 7 and installing 6,' which is an absurd solution, and Trend Micro blamed Spybot Search and Destroy for the problem. After reading Trend Micros pathetic cop out, I decided to remove their product from my system.
I am currently using NOD 32 Anti virus for my AV and I think it will be the one I will settle on. The firewall I settled on is just as amazing. Comodo (free) firewall packs a huge punch while using virtually no resources. Comodo receives a 'true stealth' rating from GRC every time I test it. With the combination of NOD32 and Comodo, my systems seem to be in peak condition.
*Update July 8 -NOD32 AV may be the best and most impressive AV I have ever run - As far as features and programming quality goes it is without equal. I am equally happy with Comodo firewall, which continues to run in 'true stealth.' Hard to believe that Comodo is a free app.
*Update July 9 -I continue to be amazed with NOD32, but I need some time to see how it protects me from threats. In a few weeks I will write a progress report about the reliability of this amazing little program.