Going back to absolute basics here. The answers on this page and a little googling have brought me to the following resolution to my issue. Steps to restart the apache service with Xampp installed:-

1. Click the start button and type CMD (if on Windows Vista or later and Apache is installed as a service make sure this is an elevated command prompt)
2. In the command window that appears type cd C:\xampp\apache\bin (the default installation path for Xampp)
3. Then type httpd -k restart

I hope that this is of use to others just starting out with running a local Apache server.

There is a small application Apache installs, usually displayed in the system tray from where you can restart Apache.

You can restart a service with many utilities, like sc.exe, but just using the shell, use

net stop Apache2.2-Zend && net start Apache2.2-Zend

In my case, the name of the service is Apache2.2-Zend. You can check the name in services.msc.

The restart action causes Apache to reload and apply its configuration, without actually restarting the process or breaking any opened client connection, causing a so called "graceful reload". You can check it by yourself with Windows Task Manager, the Apache PID (Process ID) won't change after a restart.

However, any action triggered by the option -k (they are called signals), needs the Apache service to exist in Windows services list. Therefore, if you see this error message, there are only two possible causes:

Your Apache service does not exist

Then just create it with

httpd.exe -h install

Now you should be able to send the restart signal

httpd.exe -k restart

Your Apache service has a custom name

If the service exists, but has a custom name such as "My Awesome Apache Service", then you have to specify that name when you want to send it any signal.

So, if you have installed it with

httpd.exe -k install -n "My Awesome Apache Service"

you have to restart it with

httpd.exe -k restart -n "My Awesome Apache Service"

Trying this from inside a script running under apache will not work or fail miserable, on windows as well as linux.

Usually the user that apache runs as (on any platform) does not have the privileges to restart apache, and it should stay that way.

As mentioned in the link Haim posted, you will probably need some kind of external process or script to restart the server. One way to do this would be to have a script running as a scheduled job check a control file to check when to restart the service.

I'd give more details on how to do it specifically, but I am not a windows expert.