My machine has practically ground to a halt when I'm using my browser. Checking with Task Manager reveals that with just the firefox running (plus whatever background programs) Firefox alone is using 187,000k of Memory. CPU usage for Firefox is between 30 - 70% generally at teh upper end. This is without actually doing anything to interact with open pages. All pages are static. With one or two other things this puts CPU usage peaking and maintaining 100% without any tasks being carried out. AV is McAfee (paid for) OS is XP with all updates Firefox is: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:220.127.116.11) Gecko/20091221 Firefox/3.5.7 Any ideas? It's practically crippling the machine.