Reset the page zoom on websites that look wrong: "View > Zoom > Reset" (Ctrl + 0 (zero))

See http://kb.mozillazine.org/Zoom_text_of_web_pages

See also Font size and zoom - increase the size of web pages and Font size and zoom - increase the size of web pages and Change the fonts and colors websites use

If you increased the minimum font size then try a lower setting (default is none) as a too high value can cause issues like you described.

Tools > Options > Content : Fonts & Colors: Advanced > Minimum Font Size
Tools > Options > Content : Fonts & Colors: Advanced > "Allow pages to choose their own fonts, instead of my selections above"

Hi cor-el

Thank you so much for helping with this issue. I decreased the minimum font size from 12 to 10 and that fixed the problem.

I've lost the tool bar completely, page on internet fills the screen, nothing about firefox at top can't run face book.just a white screen with tiny font ends of words just peeking into left edge. there are no menus' visible to make any changes. no bar at bottom what happened? laptop crashed yesterday while on farm town face book, but seemed to recover now cant use face book at all.

just to add. i can see internet pages fine, but fill the screen and cant see facebook at all.

I can not believe how simple this was. Over an hour of troubleshooting and wasting my time and the answer was to reset my view. Why is this answer not posted as number one on search engines?????????