Display Issues- Both Firefox And Internet Explorer Are Not Displaying Correctly?

Both Firefox and Internet Explorer are not displaying correctly. Background images do not appear at all, and some foreground images simply do not load - they don't appear at all, even as an indication that loading the image has failed. Oddly, though, there's still a blank space the size of the picture in most cases. However, there's no way to select the picture or the area where the picture would be.

some sites with style-related features do not display correctly - web-based email and forums with borders, for example (Gmail is for all intents and purposes in black and white). Internet Explorer takes the problem a step further - it increases the text size to ludicrous proportions, so that even a small chunk of text takes up several pages. I have also noticed a similar problem in semi-online programs - using McAfee VirusScan, for example (which updates through a web service) results in text that is simply too large to fit into the window, rendering the program unusable.