If it is problems with it crashing at all then, We're sorry to hear that your Firefox seems to be crashing when you open it. Please perform the following steps to give us a crash report ID that helps us find out more about the cause of the crash.

1. On the keyboard, press [Windows] The image "Windows key" does not exist. + [R]. This should bring up a Run window that contains a text field.
2. In that text field, type %APPDATA% and press Enter. An explorer window should open.
3. From that explorer window, double-click on the Mozilla folder, then double-click on Firefox and then on Crash reports. Double-click on submitted.
4. Now, you should see a list of files that contain reports. Go to View > Arrange Icons by > Modified to get the most recent files at the top of the window.
5. Open the most recent 5 files with a text editor and copy the IDs.
6. Paste each ID with bp- into the reply window on the forums.

Thanks in advance!

You can find more information and troubleshooting steps in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

Could you describe the first problem in a little more detail: Firefox does have a full screen view that eliminates toolbar. The F11 key switches in and out of full screen view. I'm not sure whether that is what you're seeing.

By default, Firefox windows are resizable using the typical methods for your OS. If you click and drag on the lower right corner, can you get the resizable window to a usable size?

Occasionally, the following might happen:

(1) The file that stores window dimensions can become corrupted and Firefox either becomes too large for your screen or won't use the whole screen when maximized. If you see that, I'll suggest how to delete the corrupted settings file.

(2) During an update, the new Firefox program files do not completely/cleanly replace the earlier ones. The fix for that is as follows:

Clean Reinstall

We use this name, but it's not about removing your settings, it's about making sure the program files are clean (no inconsistent or alien code files). As described below, this process does not disturb your existing settings. Do NOT uninstall Firefox, that's not needed.

(A) Download a fresh installer for Firefox 38.0.5 from https://www.mozilla.org/firefox/all/ to a convenient location. (Scroll down to your preferred language.)

(B) Exit out of Firefox (if applicable).

(C) Rename the program folder, either:

(64-bit Windows folder names)

C:\Program Files (x86)\Mozilla Firefox

to

C:\Program Files (x86)\OldFirefox

(32-bit Windows folder names)

C:\Program Files\Mozilla Firefox

to

C:\Program Files\OldFirefox

(D) Run the installer you downloaded in #1. It should automatically connect to your existing settings.

Can you get Firefox reinstalled?

Note: Some plugins may exist only in that OldFirefox folder. If something essential is missing, look in these folders:

• \OldFirefox\Plugins
• \OldFirefox\browser\plugins

Snoozekitty said

trying to update Norton Internet Security, got a message that it could not complete installing a patch until Firefox was not running - this was after I had closed Firefox, and the Task Manager showed no browser or applications running; was forced to restart to be able to com; is plete the Norton update

Windows 8.1 has a slightly different Task Manager than earlier versions of Windows. To see whether Firefox closed its Window but hasn't completely wound down, you now use the "Details" tab. On that tab, you can look for firefox.exe and see whether the CPU or memory usage is moving, suggesting that Firefox is just slow in shutting down, or unchanging, suggesting that Firefox hung during shutdown. To terminate firefox.exe, you can right-click and End Process. Depending on how far Firefox got in the shutdown process, at the next startup it might detect that as a crash and try to restore your previous session, or it might start normally.