Recently I had to set up a cron job for Jomsocial. The site is for a school and I am working for this site on volunteer base. The site is built on Joomla, XAMPP and 2003 Windows server.
I tried a windows scheduled task but it does not work by some reasons. I tried Joomla extension jCron, but it does not work either in this situation. I downloaded a program called "Cron for windows". But it is not free.
I set up the scheduled task on my laptop and it works, but it must work 24 hrs everyday. So I abandoned this idea.
Then I thought it can be done online. I found two free online services and I am using http://www.setcronjob.com/ . This works great and easy to set up. It works for every 5 minutes to any schedule.
The other one is http://www.onlinecronjobs.com/, but this allows only once a day and up to 5 cronjobs.
For my particular case, I just need to paste the Jomsocial cron job URL to "URL to call" in www.setcronjob.com
You need to replace www.mywebsite to yours.
The following links are my other collections during this research.
Cron for windows
Configuring cron jobs on Windows from Drupal, using Firefox.
Joomla plugin Jcron.