I removed AVG and installed Microsoft Security Essentials on my dads PC. He always shutsdown when done using the computer and this made everything SLOW when he turned it on. On a fresh bootup starting Firefox it would take about 10 - 15 seconds just to show the hourglass icon and Firefox would load about a minute after that to load. Once AVG was replaced with Microsoft Security Essentials Firefox was ready in about 15 seconds. The PC is a P4 2.4 celeron with 1GB of ram running Windows XP.