This link might help you to backup your bookmarks. https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data Take a backup of that folder, then try to reinstall firefox.

If Windows 8 is like Windows 7, then try the second path instead of the first one:

32-bit Windows: C:\Program Files\Mozilla Firefox\

64-bit Windows: C:\Program Files (x86)\Mozilla Firefox\

To make sure you have a safe backup of your bookmarks, check out this folder (paste into Start > Search) and drill down to the bookmarkbackups folder to collect a set of .json files you can copy over to your Documents or a USB flash drive, etc.

%APPDATA%\Mozilla\Firefox\Profiles

If you have multiple folders, try the one that's the most up-to-date.

Could you try Firefox's Safe Mode? That's a standard diagnostic tool to bypass interference by extensions (and some custom settings). More info: Diagnose Firefox issues using Troubleshoot Mode.

You can start Firefox in Safe Mode by holding the Shift key when you double-click the program shortcut.

In the dialog, click "Start in Safe Mode" (not Reset)

Does Firefox come up?

This may have something to do with it being Windows 8, but holding shift and double-clicking doesn't do anything?

I've never tried this myself, but the forum has a standard set of steps for a "clean reinstall" of Firefox. Although you do not remove your personal settings (AKA profile) folder during this process, a backup of that folder still is a good idea in case something goes wrong.

Certain Firefox problems can be solved by performing a Clean reinstall. This means you remove Firefox program files and then reinstall Firefox. Please follow these steps:

Note: You might want to print these steps or view them in another browser.

1. Download the latest Desktop version of Firefox from http://www.mozilla.org and save the setup file to your computer.
2. After the download finishes, close all Firefox windows (click Exit from the Firefox or File menu).
3. Delete the Firefox installation folder, which is located in one of these locations, by default:
   • Windows:
     • C:\Program Files\Mozilla Firefox
     • C:\Program Files (x86)\Mozilla Firefox
   • Mac: Delete Firefox from the Applications folder.
   • Linux: If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see Install Firefox on Linux. If you downloaded and installed the binary package from the Firefox download page, simply remove the folder firefox in your home directory.
4. Now, go ahead and reinstall Firefox:
   1. Double-click the downloaded installation file and go through the steps of the installation wizard.
   2. Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.

Please report back to see if this helped you!

The person who answered this question does in fact know what he/she is talking about. Find that location which is where the preferences are stored and create a backup. I've been there before, and yes was really tense about reinstalling firefox.

Please also see an article at: http://kb.mozillazine.org/Lost_bookmarks#

But first I would open task manager and make sure that firefox is not already running. That's happened all to many times. Thus firefox will not open.

Hope some of the above helps.

I think this might help, the only thing I don't understand is the 'installation folder' I've got browser, defaults, dictionaries, distribution, plugins, UNinstall, updated, and webapprt. I did a search for 'install' and 'installation' but there were no results.

Hi Abyssetic, perhaps it makes more sense to rename that installation/program folder rather than delete it, so that any files not present in your personal settings/profile folder can be more easily salvaged.

But I can't... find... it... It's not there. Unless you're talking about the entire Mozilla Firefox folder (which isn't what the thing you copied says,) there is no installation folder.

Hi Abyssetic, you're right, it's not called Installation. It's the entire Mozilla Firefox folder, or what I call the program folder. If you rename that to MozillaOld then you should be able to get a clean install while still having its contents available for reference.

Okay, thank you! :)

Now it says that firefox is already running, but I moved the original files and I checked task manager. Help again please? :)

To terminate running instances of Firefox on Windows:

Ctrl+Shift+Esc calls up the Task Manager

Check the Applications tab first, and End Task on any Firefox windows

Next check the Processes tab and look for any firefox.exe running there, select, and End Process

Edit: I've never tried that on Windows 8, but it has worked for as long as I can remember.

Oh okay, I didn't realize a program could run in the processes tab and not in the applications tab. Thank you, it all seems to be working fine now :)

That's great news. Many programs run hidden and only appear on that tab. Firefox should appear on both, but if there was a problem during startup, you will see that pattern of firefox.exe running or stalled, and no application window open.