If you know which web browser you use, it is usually simple to figure out which e-mail program you use. If you do not know which browser, first find out what web browser you use in the browsers section.
If you use Netscape, you most likely use Netscape Mail.
If you use Internet Explorer, you most likely use Outlook Express or Outlook. There is also the possibility that you open one of these browsers to use web-mail.

The easiest way to determine your e-mail program is by the way you get into the program. If you open Netscape 6.x and go to the "Tasks" menu and click "Mail", or if you use Netscape 4.x and go to the "Communicator" menu and click "Messenger", you use Netscape Mail.
If you use Internet Explorer 4.x or higher and click the "Mail" button on the toolbar you use Outlook Express. If you use Internet Explorer 3.x you most likely use Internet Mail (it is recommended that if this is the software you are using that you upgrade).

If you do not go through a web browser, but go straight to the program using an icon, you can tell what the program is by the look of the icon. If you open an icon that looks like a tan envelope with a black stamp, you use Eudora mail. If you open an icon that looks like a white envelope with a red stamp and two blue arrows wrapping around it, you use Outlook Express. If you open an icon that looks like a brown clock, you use Outlook.

Eudora, Outlook Express, and Outlook all display their name and version number while they are loading. If the program is already loaded up, you can find out the version number of any of them by clicking the "Help" menu and then choosing the "About X" option where 'X' is the name of your e-mail program.