After installing Microsoft November critical update KB943460 access to the internet slowed. Using Firefox 18.104.22.168 and ZoneAlarm free version 7.0.408.000, ZoneAlarm's file VSMON.exe took 100% of the cpu when opening complex web pages and took many seconds to complete the page. After uninstalling KB943460 via Add/Remove programs, response returned to normal. The same web pages opening within a second or so, and cpu rarely going above 50%.
Operating System:Windows XP Pro
Product Name:ZoneAlarm (Free)