I have used lot of antivirus in my PC. Last month like panda, kaspersky and avira. Last month I have installed norton antivirus on my computer. No doubt It has lot many good features to block malware and harmful viruses. But problem comes to me that it decreased the performance of my computer. Even my computer started taking long time after start. Also RAM utilization has been increased with it. Processor started taking more time to play videos and all that. Norton should focus on this problem.