Use this 1 minute trick you can hibernate or put your computer to sleep after any number of minutes.
Just change 3600 to any number of seconds you would like it to hibernate. For Example for 2 hours use this formula:
2 hours * 60 seconds * 60 mins = 7200 seconds (or 2 hours)
This trick can be helpful when you wish to put your computer to sleep / hibernation after the download or upload has finished or some processing is finished.
You can also schedule it for time consuming jobs like video conversion or DVD ripping etc.