Hi Could you test with another Firefox [https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles profile]?

Do you think the problem is that the Firefox window is too large for the screen? Sometimes the file that stores window and dialog dimensions becomes corrupted with nonsensical values. Since it is difficult to edit, you can rename the file to restore default settings. Open your current Firefox settings (AKA Firefox profile) folder using either * "3-bar" menu button > "?" button > Troubleshooting Information * (menu bar) Help > Troubleshooting Information * type or paste about:support in the address bar and press Enter In the first table on the page, click the "Show Folder" button. This should launch a new window listing various files and folders in Windows Explorer. Leaving that window open, switch back to Firefox and Exit, either: * "3-bar" menu button > "power" button * (menu bar) File > Exit Pause while Firefox finishes its cleanup, then rename '''xulstore.json''' to something like xulstore.old. If you see a file named localstore.rdf, rename that one to localstore.old. Start Firefox back up again. Do windows display normally again? After this procedure, the menu bar and Bookmarks Toolbar will be hidden again. To turn different bars on and off, you can use one of these methods to show the toolbar list and select the desired bars there: * right-click a blank spot on the tab bar (or the "+" button) * tap the Alt key to activate the classic menu bar > View > Toolbars * in Customize mode > Show/Hide Toolbars (see: [[Customize Firefox controls, buttons and toolbars]]) To turn on the Menu Bar, Bookmarks Toolbar, or other bars, click it on the list.