Whenever I open Firefox without Safe Mode, it will function for a few seconds, and then stop responding. (NOTE: It does not say "not responding" anywhere; it just appears nonresponsive.) Whenever a piece of the UI needs to change, (e.g., hovering over a button, typing in a search box, LOADING A WEBPAGE...) the entire area turns black. This includes EVERYTHING within the window's boundary: Title bar, tab thumbnails, the ENTIRE FRAME THAT WEB PAGES LOAD IN; all of it.

Safe Mode is currently the only fix for it, (I haven't Reset it yet;) disabling ALL the addons (including themes) didn't help.