What if you try the menu? On the same row as the zoom controls, at the right end, is a double-headed diagonal arrow for fullscreen. Does that one work?

I should note that if the cursor is in the address bar, the toolbars will stay visible. Make sure the cursor is not in the address bar before switching to full screen, or click in the page.

There's also an option to keep the tab bar and address bar displayed. If you slide the mouse pointer to the very top of the screen and right-click in an empty area of the tab bar, there is a special context menu for full screen, and the first option is "Hide Toolbars". If you see that and it doesn't have a checkmark, click it to turn auto-hiding back on.

Any progress so far?

I'm sorry I have no zoom bar.

As for arrows, do you mean the -, square or double square, and X that closes the browser?

On the menu:

Oh that works thanks.

I'm sorry if I wasn't clear, I was wondering if anyone knew how to fix my f11 key.

Okay, at least we know it's only the key and not the Full Screen function that is failing. But if Firefox recognizes other function keys, I don't know why that one would be failing. You could test:

• F10 -- activates the classic Menu bar
• F6 -- moves the cursor between the address bar and the page

Are those working?

Those both work, there might be another problem but I'm not sure what's causing it. Pressing f1 logs me out of my account and makes me log back in to windows. I don't know if it always did that because I don't normally use the f1 button.

Did you try to reboot the computer ?

Yep, it doesn't work.

I also ran a full virus scan...Nada.

Is there anything in about config that I can change?

Do other function keys like F5 or Shift+F10 (context menu) work properly ?

Do you mean that the screen dimensions do not change at all when you press F11?

If the Firefox window is already maximized then you may not notice if you go full screen if the toolbars stay visible for some reason (autohide disabled or focus on urlbar). In that case a right-click in empty space on a toolbar should reveal this.

f5 works, nothing happens when I use shift + f10.

Nothing happens when I hit f11. No changes. It doesn't take me out of maximize or make it maximized.

Is there a chance that hitting the esc button on a site while I have a maximized video player in another window could do this? Or some permutation involving escape/alt tabbing and maximized streaming players?

You can start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Something weird happened, I logged on today, nothing worked yesterday from virus scans to shutting my computer off and oddly enough it now works.

I have no idea why, but thank you everyone.