I just found out my computer has Firefox installed for windows 8. The version is up to date. The problem is that I have windows 10 and have had windows 10 from since I first downloaded Firefox. Do you not have Firefox for windows 10?
Check that you do not run Firefox in compatibility mode.
You can open the Properties of the Firefox desktop shortcut via the right-click context menu and check the "Compatibility" tab.
Make sure that all items are deselected in the "Compatibility" tab of the Properties window.