You can find out what your fonts are in your Internet Explorer browser by selecting VIEW > SOURCE from the menu bar at the top.
This will give you the source code of your webpage in NotePad or WordPad. From either of these Pads, select SEARCH or FIND and enter "font" in the query field. When you do the search, it will give you every example of the font type your page has, like this: FONT FACE="Arial"
From my quick look on your first site, it seems you have have mainly Arial.
Some browsers will change your fonts to another style if there are no alternatives selected in the HTML code.
For example, your web page's source code has only "Arial" showing for its font selection. So your Netscape browser will give Courier as a default font if it can't find Arial in its fonts folder.
To avoid that, and keeping more control over what your viewers see, replace the single "Arial" with this string: "arial,helvetica,verdana"
Your browser will then check through each of these alternatives until one appears. Goodbye Courier!