-> Tap ALT key or press F10 to show the Menu Bar

-> go to Help Menu -> select "Restart with Add-ons Disabled"

Firefox will close then it will open up with just basic Firefox. Now do this:

-> Update Firefox to the latest version by going to Help Menu -> About Firefox -> click Check for Updates -> if an updated version is found then download the latest version and install it. After that follow these steps:

-> Update ALL your Firefox Plug-ins https://www.mozilla.com/en-US/plugincheck/

-> go to View Menu -> Toolbars -> unselect All Unwanted toolbars

-> go Tools Menu -> Clear Recent History -> Time range to clear: select EVERYTHING -> click Details (small arrow) button -> place Checkmarks on ALL Options -> click "Clear Now"

-> go to Tools Menu -> Options -> General -> In Startup section click "Reset to Default" -> Click OK on Options window

-> go to Tools Menu -> Options -> General -> When Firefox starts : select "Show My Home Page" -> Type the address of the website which you want to be your HomePage e.g. http:www.google.com -> place Checkmark on "Show the Downloads window when downloading a file" -> select Radio Button option2 "Always ask me where to save files"

-> go to Tools Menu -> Options -> Content -> place Checkmarks on:

1) Block Pop-up windows 2) Load images automatically 3) Enable JavaScript

-> go to Tools Menu -> Options -> Privacy -> History section -> Firefox will: select "Use custom settings for history" -> Remove Checkmark from "Permanent Private Browsing mode" -> place CHECKMARKS on:

1) Remember my Browsing History 2) Remember Download History 3) Remember Search History 4) Accept Cookies from sites -> select "Exceptions..." button -> Click "Remove All Sites" at the bottom of "Exception - Cookies" window

   4a) Accept Third-party Cookies -> under "Keep Until" select "They Expire"

-> REMOVE CHECKMARK from CLEAR HISTORY WHEN FIREFOX CLOSES

-> go to Tools Menu -> Options -> Security -> place Checkmarks on:

1) Warn me when sites try to install add-ons 2) Block reported attack sites 3) Block reported web forgeries 4) Remember Passwords for sites

-> Click OK on Options window

-> click the Favicon (small drop down menu icon) on Firefox SearchBar (its position is on the Right side of the Address Bar) -> click "Manage Search Engines" -> select all Unwanted Search Engines and click Remove -> click OK

-> go to Tools Menu -> Add-ons -> Extensions section -> REMOVE All Unwanted/Suspicious Extensions (Add-ons) -> Restart Firefox

You can enable your Known & Trustworthy Add-ons later. Check and tell if its working.

Go to:

C:\Users\YourUserName\AppData\Roaming\Mozilla\Firefox\Profiles\something.default

Delete prefs.js, or edit it if you know what you are doing.