When your computer writes data into a file on your hard drive, it's not always able to place all of the data together. A section of a file might be written near the beginning of the disc, the rest of that file could be written near the end.
This causes programs to run slowly, as the computer spends time retrieving the file fragments from all over the disk.
Defragmenting your disk volume arranges files (and free space) in an orderly manner, reducing the time taken to read a file.[1] There are various tools available to defragment the computer, and one version is included with MS Windows. Here are some methods for defragmenting your Windows computer.
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