Use Window's Task Scheduler / Manager (run taskschd.msc) to do this...
It's like cron but for Windows.
You can give it a URL to hit every so often (via executing cURL, wget, powershell, VBS, IE/Firefox/Chrome), or use it to directly execute a PHP script via php.exe.
For example, if I wanted to run a PHP file (via my Wamp-Developer), I would just add a task that executes this...
C:\WampDeveloper\Components\Php\php.exe -f "C:\my_php_file.php"
You can specifiy for it to also use / or not use the php.ini file (check php --help).
Or..
C:\WampDeveloper\Tools\curl\curl.exe http://localhost/my_php_file.php
You can HEAD, POST, login, etc with cURL...
http://curl.haxx.se/docs/manual.html
Since you're using WampServer, you'd just update the Wamp-Developer paths above and it should work (I don't know where WampServer or Xampp places php or curl).