Defragmenting The Hard Drive
Defragmenting your harddrive(s) is a task that you must perform if you frequently copy and delete files (especially small ones) from your harddrive. Essentially, defragmenting the harddrive is nothing more than rearranging free and used blocks.
The idea is that if all used blocks and all free blocks are grouped separately, searching for files on your harddrive will be faster because all the blocks of a file will be grouped together and not scattered all around the harddrive. How data is written in files and on the disk is complicated to explain in a tip but just take it for granted that defragmentation is a general housekeeping task and has to be performed regularly.
You can make defragmentation a scheduled task that runs at specified times (i.e. at night when you computer is idle) or you can start it at any time you like.
To start the degragmenter, right-click My Computer icon on the desktop and select Manage. Then go to Storage and click Disk Defragmenter. Select the drive you want to defragment and click the Defragment button (or you may first click Analyze button to see if the drive needs defragmenting or not).