Here is a PHP mail library that works with Gmail SMTP and Xampp:
Download all code as a zip and unzip somewhre in htdocs.
In the unzipped folder go to
find the file gmail.phps and copy the file
paste it and rename to gmail.php
Edit the file and add your user details. For the sake of the test let the recipient be yourself.
If you fire off the file and get a mail then it works.
And it worked for me in Xampp.