Using these steps you might be able to sort out your problem

• Pressing ALT key or press F10 to show the Menu Bar

check if your all plugins is updated if no,then update them through Firefox Plug-ins https://www.mozilla.com/en-US/plugincheck/

• Now Go to View Menu>Zoom>click "Reset"

• Next to View Menu>Page Style>select "Basic Page Style"

• After that toggle to Tools Menu>Options>Content> tick on:

1. Load images automatically
2. Block Pop-up windows
3. Enable JavaScript

Replay if it works

You can set the layout.css.devPixelsPerPx pref on the about:config page to 1.0 or on Windows 8 to 1.25 and if necessary adjust layout.css.devPixelsPerPx starting from 1.0 in 0.1 or 0.05 steps (1.1 or 0.9) to make icons show correctly.

• http://kb.mozillazine.org/about:config

See also:

• https://support.mozilla.org/kb/forum-response-Zoom-feature-on-Firefox-22

Use an extension to adjust the text size in the user interface and the page zoom in the browser window.

You can look at this extension to adjust the font size for the user interface.

• Theme Font & Size Changer: https://addons.mozilla.org/firefox/addon/theme-font-size-changer/

You can look at the Default FullZoom Level or NoScript extension if web pages need to be adjusted after changing layout.css.devPixelsPerPx.

• Default FullZoom Level: https://addons.mozilla.org/firefox/addon/default-fullzoom-level/
• NoSquint: https://addons.mozilla.org/firefox/addon/nosquint/