I have a form on my page. When the user hits the Send button - it\'s supposed to send an email with the details he entered in the form. Up until recently the form was hosted
In a windows environment PHP uses SMTP insted of the Linux binary sendmail (or replacement)
You need to edit php.ini according to this page to be able to send e-mail via the mail() function.
On Linux, PHP uses an application called sendmail. Of course there is no similar applicaion on Windows. As php.ini file says, to be able to work with mail function, you need to setup mail server coordinates. If You don't have mail server, it is not possible to send emails from PHP. Of course You could use some external server like gmail.