This is a very simple mail component test that checks for a few common mail components on your server.
Code:
<%
Sub errorCheck(errObj)
    if errObj <> 0 then
        response.write "This component is not available on this server.<br>"
        err.clear 
    else
        response.write "This component is available on this server.<br>"
    end if

    response.write "</p>"
End Sub

Dim obTest
On Error Resume Next
 
Set obTest = Server.CreateObject("CDONTS.NEWMAIL")
Response.write "<P><strong>Testing CDONTS mail component...</strong><br>"
errorCheck(err)
 
Set obTest = Server.CreateObject("JMAIL.SMTPMAIL")
Response.write "<P><strong>Testing JMail component...</strong><br>"
errorCheck(err)
 
Set obTest = Server.CreateObject("Persits.MailSender")
Response.write "<P><strong>Testing ASPEmail component...</strong><br>"
errorCheck(err)
 
Set obTest = Server.CreateObject("CDO.MESSAGE")
Response.write "<P><strong>Testing CDO mail component...</strong><br>"
errorCheck(err)
 
Set obTest = Nothing
%>
Save this script in a new page and, of course, save it with .asp extension. Simply run it and it will tell which, if any, mail components are installed.
It's simple to add new mail components to this, also.