1, first find "Disk Defragmenter" from the Start menu. You can choose Start-All Programs--attachments--System Tools--Disk Defragmenter, or you can find them directly in the search bar.
2. Under current status, select the disk that you want to defragment. Here, if you cannot determine if there is fragmentation on your disk, you can select the analysis disk first. Of course, if you are certain that you know that a disk must be fragmented, you can also select defragment directly.
After the analysis disk is finished, you can choose to defragment the disks based on the results of the analysis. You should defragment the disk as long as you check for more than 10% percent of fragmentation on the disk in the last run time. Just click on "Disk Defragmenter" to help your Win7 to lighten up.