FindWord allows you to register one or more index runs with the Windows-Scheduler, to be run automatically at given times.
Go thro "Start - All Programs - Control Panel" and click on "Scheduler":
Scheduler allows you to specify exactly how and when (e.g. after 20 Minutes idle time, or at 3 o'clock in the night) which index run is to be started:
Furthermore you can specify for each run if only the previously indexed files are to be checked for changes, or whether newly created files and directories are also to be included.