LiveAgent has files jobs.php and queue.php that need to be executed periodically. On Linux servers this is solved by cron.
Windows server offers tool called "Task Scheduler" that provides the ability to schedule the launch of programs or scripts at pre-defined times or after specified time intervals.
You need to create a Task Scheuler entry which will execute the following command:
"C:\<Path_to_PHP_executable>\php.exe" -f "C:\<Path_to_LiveAgent_installation>\scripts\jobs.php"
Do not forget to replace "<Path_to_PHP_executable>" with the real path leading to the php.exe file in the PHP installation in your server and "<Path_to_LiveAgent_installation>" with the real path leading to the installation of Live Agent on your server.