As allllec suggested, a new profile should fix it if it's a preference issue - but try it before you copy anything across.
If you reduce the text size, it shouldn't look like that (I just tried it).
Check Tools -> Options -> Content -> Fonts & Colours.
The Default Font should be Times New Roman, size 16. In the box you get from the Advanced button, the values should be (for Western):
Proportional: Serif, 16pt
Serif: Times New Roman
Sans-serif: Arial
Monospace: Courier New, 13pt
Minimum font size: None
Try clearing the cache too.