Schedule Disk Defrag in Vista
 

Your computer is scheduled to undergo disk defragment every week which is one of the features for system maintenance of Windows Vista. By default, it is scheduled to run at 1am during Wednesdays. Unfortunately, not all people are awake at this time, unless you are an insomniac. And since to defrag means leaving you computer open, you either wait for that time or you leave your computer open for the whole night once a week, making your electric bills shoot up. It is a good thing that you can actually alter the schedule of your defragment. To access your defragment utility, enter in defrag in the Start menu search box and then enter. Go through the UAC prompt until you reach the screen wherein you can disable automatic defrag. Just uncheck the box beside the option that says to Defrag automatically. Or you can also try changing the schedule to a time that you are actually using your computer so as to save in electricity as well as the effort of being awake at that late time.