Which email client does user have?

[A. Turtle]

I am attempting to develop a database, to be sent to clients as runtime enabled, for information gathering. In it there is a command button which opens the user's email client to allow the user to request help, further information, whatever.

Unfortunately the code associated with this button includes:

stAppName = "Outlook.exe"

It is more than possible that the user will not have Outlook as their email client. Is there any way that Access can determine the email client in use? This can then be held as a variable and used in place of "Outlook.exe" in the above.