I am at my wits end with Firefox. Several weeks back a problem started where scrolling and switching between tabs is very jerky, ie. Firefox keeps hooking the mouse every couple of seconds. This makes for a very unpleasant browsing experience as the whole browser becomes very sluggish. - I have downgraded to earlier 3.5.x versions and the problems remains. - I have disabled all plugins - problem remains - I have told my antivirus to bypass any checking on the mozilla folders - problem remains - It happens almost immediately after opening FF so I doubt it's a memory leak either - I have created new profiles to test - problem remains - I then re-upgraded t0 3.6.8 after installing about 9 older versions - problem exists in all of them. - Even typing here, every few seconds there is a pause in my typing lasting about 1-2 seconds and then the last few letters I typed appear, so the hooking / sluggishness is not just related to scrolling / switching tabs, it's to do with anything in the browser. I have wracked my brains trying to isolate this problem but I am lost for a solution. I am waiting to hear back from ESET to hear if they have any clients experiencing this problem with ESET Smart security 4.2. I even upgraded to the latest ESET this morning but that has not helped. I upgraded video drivers yesterday, also no help. I'm losing hair fast with this most annoying issue, can anyone share some words of wisdom or anything I might have missed checking on??? Something I also noticed when switching between all the older versions the last few days, all older versions of Firefox 3.5.x are probably 200% faster at loading pages than any version of 3.6.x. I did numerous downgrades and upgrades which all verified this. I have 56 tabs open in my browser on a daily basis and 3.6.x is terribly slow at loading them so I actually might just switch back to 3.5.x until Mozilla actually fix this in 3.6 but this hooking issue I need to isolate and kill. Thanks in advance from a loyal but VERY frustrated Firefox user.