First go to Tools >> Options >> Privacy >> Firefox will change to Never remember history, restart Firefox then clear your data, or if you want only clear these data only clear your recent history:

• Clear recent history

Problems with bookmarks and history not working properly can be caused by a corrupted places.sqlite database file.

You can check for problems with the places.sqlite database file in the Firefox profile folder.

• http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox
• https://support.mozilla.org/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe Mode start window.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Your System Details List shows that you have a user.js file in the profile folder to initialize prefs each time Firefox starts.

The user.js file is only present if you or other software has created this file and normally it wouldn't be there. You can check its content with a plain text editor (right-click: Open with) if you didn't create this file yourself.

The user.js file is read each time Firefox is started and initializes preferences to the value specified in this file, so preferences set via user.js can only be changed temporarily for the current session.

Delete a possible user.js file and numbered prefs-##.js files and rename (or delete) the prefs.js file to reset all prefs to the default value including prefs set via user.js and prefs that are no longer supported in the current Firefox release.

• http://kb.mozillazine.org/Preferences_not_saved

You can use this button to go to the currently used Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)

This did not work. I have tried all the suggestions from Firefox, still nothing will clear my history, autofils and drop down suggestions.

I found the user.js file and preferences, however I do not know if I should delete all, or any without regrets and/or a way to restore.

Firefox doesn't come with a user.js file. If you don't recall creating that file yourself, just delete it - as "something" else created that file "for you" and in the process changed and locked a setting that you specifically didn't necessarily want to "lock".

Here is a brief explanation about the user.js file.
http://kb.mozillazine.org/User.js_file

What is the content of the user.js if you open this file in a text editor like Notepad (right-click: Open with)?

Full contents :

user_pref("yahoo.ytff.general.dontshowhpoffer", true);
user_pref("network.http.pipelining", true);
user_pref("network.http.pipelining.maxrequests", 8);
user_pref("network.http.proxy.pipelining", true);
user_pref("network.http.request.max-start-delay", 0);
user_pref("network.http.max-connections", 48);
user_pref("network.http.max-connections-per-server", 16);
user_pref("network.http.max-persistent-connections-per-proxy", 16);
user_pref("network.http.max-persistent-connections-per-server", 8);
user_pref("browser.turbo.enabled", true);
user_pref("browser.display.show_image_placeholders", true);
user_pref("browser.chrome.favicons", false);
user_pref("browser.urlbar.autocomplete.enabled", true);
user_pref("browser.urlbar.autofill", true);
user_pref("browser.cache.memory.capacity", 65536);
user_pref("content.notify.ontimer", true);
user_pref("content.notify.backoffcount", 5);
user_pref("content.interrupt.parsing", true);
user_pref("content.notify.interval", 750000);
user_pref("content.switch.threshold", 750000);
user_pref("content.max.tokenizing.time", 2250000);
user_pref("plugin.expose_full_path", true);
user_pref("ui.submenuDelay", 0);
user_pref("nglayout.initialpaint.delay", 0);

I do use an Internet Boost, by the way. Can you help me with selection deletes or resolution?

You do not really need these prefs to be modified from their default value, so you can remove this file and possibly also the prefs.js file to reset the value of the prefs that has been stored there. That is easier than work your way through the about:config page and reset them all individually. Note that this will reset all changes that you made yourself, so you will have to redo them. A backup copy to the prefs.js file might help to check some settings.

Please tell me how to get to this file and delete it completely.

You can use this button to go to the currently used Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)

• http://kb.mozillazine.org/Profile_folder_-_Firefox

Note that the "AppData" folder in Windows Vista and later Window 7+ versions and the "Application Data" folder in XP/Win2K are hidden folders.

• http://kb.mozillazine.org/Show_hidden_files_and_folders

Note that Windows hides some file extensions by default.
Among them are .html and .ini and .js and .txt, so you may only see the name without file extension.
You can see the real file type (file extension) in the properties of the file via the right-click context menu in Windows Explorer.

See also:

• http://kb.mozillazine.org/Preferences_not_saved

I've followed directions above to the best of my ability but i cannot find a file location.

Which file can't you find?

You already posted the content of the user.js file, so you were able to find this file previously and this file is also in the Firefox profile folder.
If you already have removed this user.js file then it will no longer be there.
If you mean deleting the prefs.js file to reset the prefs then this prefs.js file should be in the same location, but will only show as Prefs file without the .js file extension in Windows Explorer because Windows hides the .js file extension.

• http://kb.mozillazine.org/Profile_folder_-_Firefox