if you're having problems getting sendmail.exe to work, here's a few steps that you can take in order to determine where things are going wrong.
due to a bug in php, you won't be able to use a path which contains a space (such as "c:\program files"). this bug has been fixed in php 5.3.
first you need to ensure that your host application is configured correctly, and trying to execute sendmail.exe.
an easy way to ensure that sendmail.exe is being executed is to download process monitor from microsoft.
configure the filters to only show calls to sendmail.exe:
then trigger an email with your host application.
sendmail.exe is not in the correct directory:
no permissions to open/execute sendmail.exe:
sendmail.exe called successfully:
if sendmail.exe is being called successfully, enable debugging in sendmail.ini, trigger and send me the contents of debug.log.