Disk defragmenter:Defragmenting a disk is like sorting and arranging items in a storage room; boxes holding similar things are combined, and all the boxes in the room are stacked neatly to create more space. Defragmenting does not change any of the files' contents, and does not affect anything you see on the screen (documents, shortcuts on the desktop, etc. )Disk fragmentation causes files on your computer to be scattered on totally different parts of the disk. This typically happens after you install some application or delete a large number of files. Disk fragmentation occurs when a file is broken up into pieces to fit on the disk. Because files are perpetually being written, deleted, and resized, fragmentation may be a natural occurrence. once a file is spread out over many locations, it takes longer to read and write leading to slow computer performance. Hence, a disk defragmenter is to Rearrange blocks of data to store files in contiguous sectors.