ahk2chan

You can use the AT command-line command to schedule task execution in Windows environment, similar to cron job in the Unix / Linux environment.

You can also do it through a more user-friendly way, by going to Start > Accessories > System Tools > Scheduled Tasks.

Here is a link to Microsoft knowledge base that describe how to use the at command.  I think the paper is actually on Windows 2000 but it does apply to other Windows environment I believe.