From the start menu select (left click) Computer or My Computer then right click on the "C" or primary drive, select properties and then next to the graphic display near the center of the panel that appears select "Disk Clean-up". After a while shorter or longer depending on degree of maintenance another pane with a drop down list - check all boxes then at the top of this pane select Other Options Tab. Select the lower right button to remove all but the most recent restore point, then choose okay each time prompted and allow the system to clear the disc. Then on the start menu right click Computer and select Properties, then select advanced settings, then choose the Advanced Tab and click the settings button for Performance. This is another time to choose the Advanced Tab and then select "Change" button choose "NO Page File" and then click on the Apply. The computer will need to reboot and then you need follow the previous directions to return to the Performance settings and change this time to "System Managed Page File" and choose "Apply" then the system will be ready for a drefragmentation of the "C" or Primary drive.

 I like the Smart Defrag Program made by Obit, it's included in a program called "System One Care-Free" yes it's free, very comprehensive, will help keep your computer shaped-up and  it's fast and useful; you can download it here; the download will begin automatically http://majorgeeks.com/downloadget.phpid=5927&file=15&evp=42472cd3f1aa59886cf05e3f3046518e