Reload the webpage while bypassing the cache using one of the following steps:

• Hold down the Shift key and click the Reload button with a left click.

OR

• Press Ctrl + F5 or Ctrl + Shift + R (Windows and Linux)
• Press Command + Shift + R (Mac)

Let us know if this solves the issues you are having.

Thanks for your help but I think the problem is with Yahoo as their new E-mail is full of issues.

Reset the page zoom on pages that cause problems.

• View > Zoom > Reset (Ctrl+0 (zero); Command+0 on Mac)

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

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"

You can right-click text and chose "Inspect Element" to open the built-in Inspector and check the Fonts tab to see which font is used for this text.

If you have made changes to Advanced font settings like increasing the minimum/default font size then try the default minimum setting "none" and the default font size 16 in case the current setting is causing problems.

• Tools > Options > Content : Fonts & Colors > Advanced > Minimum Font Size (none)

Make sure that you allow pages to choose their own fonts.

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

Thanks for the suggestions. I have tried them but problem would appear to be be embedded in Yahoo Mail and not affected by browser.