In your experience of owning a computer, you have undoubtedly had someone recommend that defragging your hard drive will make it run faster.  This is mostly true, but there are some underlying concepts that you should know.

Your computer stores long term data on your hard drive.  Like any good filing system, it works best when this data is contiguous.  Unfortunately, normal every day use of your computer causes your data to become fragmented, meaning that once contiguous pieces of data are now stored on separate parts of the hard drive.  This does not necessarialy slow down your computer but it increases the amount of time it takes for your hard drive to find, or seek, the data you are looking for.  A heavily fragmented drive will spend more time seeking than a newly defragmented drive and you will notice a significant gain in drive performance.

When you should defragment is entirely a personal preference.  We recommend that the average user should analyze their hard drive once monthly.  The analysis will tell you whether a defragment is necessary.  It will most likely tell you to defragment 3-4 times a year if you analyze monthly.  Individuals that use their computer 4+ hours a day and/or work with large files will probably need to defragment 6-8 times a year.  If the analysis tells you to defrag every month for 3 months straight, begin analyzing your hard drive every other week for optimum performance.

If you do not know how to defragment your hard drive, please see our how-to articles or contact a computer repair technician.