Firefox is slowing down. More I am using Firefox then more I have to wait for reaction(open tab, klick on button etc.)

Question

For more that one year everything was ok with Firefox. Even after upgrades of my PC everything was just fine. About 2 months ago when I opened Firefox I noticed that he is slowing down(not PC only browser). More time I spend on Firefox longer takes everything-from tab opening, button klicks, closing tabs etc. It looks like it freeze for period of second or longer and come back to normal for few seconds. I was trying to ckeck that on many any only one opened tab. But result was same. I deinstalled Firefox, deleted related folders and installed him one more time with updates and with updated Adobe Flash but without changes. Still crap. Please HELP!!!

Answer 1

The proper way to close Firefox is through the File menu "Exit" or the equivalent with the Firefox button.
More detail in item '''#38 Firefox already running '''
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[http://dmcritchie.mvps.org/firefox/firefox-problems.htm#fx4interface Fix Firefox 4.0 toolbar user interface, problems (Make Firefox 4.0 look like 3.6) (#fx4interface)]
Firefox already running, to properly shutdown Firefox when closing the last window use File → Exit/Quit (or Firefox button → Exit). Closing Firefox with the [X] in the upper right corner closes the window ("Ctrl+W") but that does not necessarily close Firefox if it has subtasks running. If you want to close and reopen Firefox use the "Restart" within Add-ons if you made a change requiring a restart, or install "[https://addons.mozilla.org/firefox/addon/restartless-restart/ Restartless Restart]" ("Ctrl+Alt+R") which will allow you to take Firefox down and restart without having to check the Windows Task Manager to see if Firefox first actually ended. [http://kb.mozillazine.org/Firefox_hangs Firefox hangs]