Ahh, got it. Look for a setting that specifically controls the font size for monospaced text.
For example, in Firefox, go to Options > Content > Fonts & Colors > click the Advanced button, and UNcheck the box that says “Allow pages to choose their own fonts...” then change the font size for “Monospaced” to something biggish, say 20pts.
You should notice the difference immediately.
You are SUCH a good son! *HUG*