high memory "not responding"

[HOW]

For some time now I have been having problems with high memory usage in Firefox (as reported in Windows Task Manager) It uses more memory than all running programs combined. It starts out at about 500,000K and often climbs over 1,000,000k.

Clicking on any web page results in a "Not Responding" notice and it can take 20-30 seconds before Firefox will be able to respond. In fact, I click anywhere on a page, I get the "Not Responding" notice, it goes away after 10 seconds, I click again, and it goes into "Not Responding" mode again, and I can do this a dozen times over a minute before I am able to click on an item box, for instance to enter my user name in order to ask a question on this forum.

I recently ran Junkware Removal Tool (Malwarebytes) and it removed these Firefox related items, to no avail.

Deleted the following from C:\Users\User\AppData\Roaming\Mozilla\Firefox\Profiles\tb2isrrv.default-1394367927409\prefs.js
user_pref(browser.urlbar.suggest.searches, false);

In fact the above file must have been re-inserted as it was again removed the next day when I ran JRT.

[DanRaisch]

C:\Users\User\AppData\Roaming\Mozilla\Firefox\Profiles\tb2isrrv.default-1394367927409\prefs.js
user_pref(browser.urlbar.suggest.searches, false);

That's not a file, it's a setting in Firefox's configuration file and should not have been modified by that utility.
Have you tried starting Firefox in Mozilla Safe Mode? http://kb.mozillazine.org/Safe_mode
If no improvement using Safe Mode, do you have the same problem if you create a new profile and test it with no extensions or non-default themes installed?
http://kb.mozillazine.org/Profile_Manager
and
http://kb.mozillazine.org/Creating_a_ne ... on_Windows