For a long time now, I’ve been having problems with my Firefox (1.5.0.7) and Internet Explorer (ver 6) browsers. The colors in Firefox won’t appear while in Internet Explorer, the fonts were too big. I finally found the answer here. It turns out that I have to uncheck the Use High Contrast setting in Windows XP:

Windows users) Start Menu -> Control Panel -> Accessibility -> Display -> uncheck “Use High Contrast”, restart the application

Lesson? Proceed to the support area of the software concerned (in this case, Firefox) immediately!