This just a text at the moment to teach myself how to change the fonts in Linux Mint ( Nadia ) um i found out this finally after hacking on the problem for a day or 2 on 3 different machines that I recently installed Mint onto ( you can see that I like this one a lot ) 

Um but like all Gnome 2 desktops its a bit tricky to get right with the settings so the X-Server and Desktop work as you would like them to.  With this setup you should be up and running with your HDTV box.  Note this doesn't go into setting up the Tuner Card, thats a story for another day.

First a screenshot for you to see the result. ( click on it for larger image ) Note first change the fonts for the system I made all change to 16 from the default setting of 10 that it has after your system install ( too small for long range viewing as a HDTV system needs ).
Here is the fonts page you need to change this first as I changed the theme first on the other computer and X or Mint didn't like it and the fonts on the menu bar didn't change.

This is the next step ( click for larger )

Once you have clicked on the Menu button at the bottom left side of the screen go to appearance button and click to get the Appearance Preferences window now click on Customise then I chose Clearlooks and something on the Window Border tab .... that you like and is easy to see.
Linux TV card for more information on setting up the Hauppage TV tuner device using Kaffeine.