Your settings in Windows can affect Firefox.
Windows Control Panel > Internet Options.
(1) Restore IE's Security Zone policy for the "Internet" zone to "Medium-High" security.
On the Security tab, make sure Internet is selected, then if the level is not set to Medium-High, click "Default Level". It should become Medium-High.
(2) Check the Restricted Site list.
On the Security tab, select Restricted Sites, then click the Sites button to make sure sites important to you are not listed there.
“Every atom in your body came from a star that exploded and the atoms in your left hand probably came from a different star than your right hand. It really is the most poetic thing I know about physics...you are all stardust.”― Lawrence M. Krauss
A 1792 U.S. penny, designed in part by Thomas Jefferson and George Washington, reads “Liberty Parent of Science & Industry.”