a) You're using a default stationery with the font size pre-set which overrides any manual settings you try to input

b) You're using plain text format and you're adjusting the font size which would be applicable only if you were using HTML formatted email. You can set this option even if your Outlook Express is set to plain text email (strangely enough). Although it would have no effect on your plain text email, should you switch to HTML formatted email, the settings you chose would apply. So if you're composing messages in Plain Text you'll need to switch to HTML for font size settings to work.

The most likely of these is that you have set a default stationery. In other words, every time you compose an email, you're composing the message on your chosen default stationery - and if you continue to leave that stationery set as default, you're going to continue to be unable to change (override) the font settings of the stationery.

There are two possible solutions to this:

1. Don't use the default stationery
2. Change the font settings within the stationery code itself (which requires that you understand a bit about HTML codes and perhaps CSS (style sheets) too.

Since changing the stationery code itself is more difficult if you don't know anything about HTML and since there are so many ways of setting font-size in base HTML code of stationery and we don't have the space to cover all those ways here; your best bet would be to simply not use any default stationery at all. If you have a particular stationery you like to use you can manually choose it when you really want to use it, with the understanding, of course, if you do you will not have the option of changing font size manually using Outlook Express. When you selected the default stationery Outlook Express notifies you that "stationery fonts will be used". That means Outlook Express will use the fonts specified in the stationery (colors, font type, font style, and size) and you won't be able to change it if you want to use that stationery.

To stop Outlook Express from loading your default stationery each time you compose a message - open Outlook Express, click on Tools, Options, and uncheck the box next to "mail" under the stationery section of the dialog (which is about in the middle of the dialog window). Click Apply, OK. Now close Outlook Express and reopen it.

The next time you compose an email (assuming your Outlook Express is set to HTML format for composing email) you'll have the option of adjust font-size right from the Outlook Express compose window, without going into "Tools" "Options" "Compose".

From the compose toolbar (at the top of your compose window) you can change the font (red ellipse) and the size (green ellipse) - as well as use Bold, Italic, Underline styles, on-the-fly while writing an email.