Installed Add Ons, however ontinue to be prompted to install everytime firefox is launched. How do I make it go away?

Question

We received the screen to install ad block plus 1.3.9 and Garmin Commun 2.9.3.1. Both installed and then we were prompted to restart Firefox. Clicked on the restart firefox button and firefox restarted. Now each time we click Firefox, the same screen appears with a long list of Java stuff. What do we need to do so that this screen doesn't appear?

Answer 1

forget that. do this: Close Firefox -> Start Firefox in Safe Mode by Holding down the SHIFT key while starting Firefox -> Safe Mode window appears -> click "Continue in Safe Mode"
-> 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 -> ''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.