Does this happen on every web page?

This indicates a problem with the font that is used to display the text.

You can use this extension to see which fonts are used in selected text (right-click: "Show fonts in selection").

• fontinfo: https://addons.mozilla.org/firefox/addon/fontinfo/

You can do a font test to see if you can identify corrupted font(s).

• http://browserspy.dk/fonts-flash.php?detail=1

You can try different default fonts and temporarily disable website fonts to test the selected default font.

• Tools > Options > Content : Fonts & Colors > Advanced
• [ ] "Allow pages to choose their own fonts, instead of my selections above"

This does not happen on all of the web pages. If I run this program as admin. it does not happen either but then java is disabled along with all other apps. If I run as admin. and then look at the plug ins I see that the Java Deployment Toolkit 7.0.250.17 10.25.2.17 is at Ask to Activate and can not be activated.