Defragmentation is a process by which your operating system (ie.. Windows) reorganizes your files in such a manner as to allow faster, more efficient, access to them. The symptoms of a fragmented hard drive start with increasingly poor performance, shown in a practical sense by your system seeming to get slower and slower and your hard drive grinding ever harder to complete simple tasks. Other signs can include the same types of Windows errors that precede the need for a Scandisk, such as Illegal Operation and Invalid Page Fault errors, etc...

To define it practically, imagine you have a large filing cabinet full of file folders, each containing very specific information (much like your hard disk drive). If over time you continually pull papers from specific spots and put them back in different places, while continuing to add new files, eventually you end up with a large mess. All the information is there, but it's increasingly hard to find, and in some cases you might not find what you are looking for at all. Defragmentating is analogous to sitting down and reorganizing the entire cabinet, putting all the files back into the right folders where they are easily accessible. This is a simplified explanation, but it is much the same for your hard drive.

Defragmenting your hard drive every month or two is an excellent way to maintain peak system performance. If you have noticed Windows running more slowly than usual, or if you have not defragmented recently, you might want to do so. Be forewarned that this is a good thing to do just before going to bed, in most cases you will not be able to use the computer while it's defragmenting your files - you will simply cause the whole process to restart repeatedly - and generally it takes several hours to complete, depending on your processor speed and the size of your hard disk drive.

How to Defragment your Hard Drive: