Here is a link to download defraggler, a free and great program to defragment your hard drive. http://www.piriform.com/defraggler/download/slim/downloadfile
Run the install file after its downloaded.
After its installed run the program.
While in defraggler press the alt key and arrow to the right until you are at the settings menu While in the settings menu press c to open the schedule
After the schedule screen has opened you will be in a list of drives on your computer. Press the arrow keys until you are on your C: drive
Press tab and you should be on an item that says schedule defragmentation for selected drive. If the check box is unchecked, press the space bar to check it.
Press tab and you will be in a list of how often you want to run the defragmentation.
I suggest monthly for most people, unless you are doing heavy graphics or video editing. Press tab again and you will be in a date field.
Press your right arrow key to move over to the day part of the date. Press the up arrow to increase the date by one day.
Press tab again and you can change the time at which defragmentation will happen.
Pick a time of day when you are asleep or will be away from home. For example, if you are usually asleep at 4:00 am, that might be a good time to run this process, as long as your computer is on. Press the up or down arrow to change time
You can skip the next two items and press tab until you get to the ok button. Press space or enter on ok and you are done.
You can exit defraggler and your computer will run this program once a month at the time you selected, no action is needed on your part.