[TYPO3] [OT] Mail function on windows machine

[Nige]

Hi,

I have 2 sites running...php4.4.0/typo3 3.7.0 and php4.1.2/typo3 3.6.2 
(2 separate sites), both running on windows machines with Apache 2.0.54.

Both sites have some email forms, which worked just fine until a few 
weeks ago when the mails just stopped. I cannot think of anything that 
has been changed on either installation. The sendmail test in the 
install tool also fails.

On both servers the SMTP directive in php.ini is pointing to a valid 
mail server, and the recipient email addresses in the mail forms on the 
sites are also valid addresses.

Is there another configuration setting in php.ini , apache or typo3 that 
  you know of that I may have forgotten about?

Nige