Does Disk Defragment makes your computer faster?

Yes.. it reduces the time taken by the Hard drive to search for a file . thus, improving performance..

when you delete files and copy/make new ones.. they may appear sorted ( as in folders and disk drives).. but inside the Hard drive they are not in the same place but scattered over the magnetic disks (platters).

So when you open a program.. the hard disk has to look for the essential files all over the platters and hard disks have 1 - 3 platters.. so searching all of them is time taking

after the Defrag all the files are organised and when u open the same program the hard drive has to look only in one location to get all the essential files..reducing access time.