If you want to keep your PC in top shape, defragmenting the hard drive should be second nature.
Fragmentation occurs as you use your PC. Writing and erasing information from your hard drive leads to packets of data being stored non-contiguously. This slows things down because every time your PC looks for the file it needs, it has to hunt all over the hard drive, rather than being able to find everything in one place.
Defragmentation software helps to reverse this process. In essence it reorganises your hard drive so data is stored in a more logical fashion, thus improving the performance of your PC. If you do this regularly you may not notice the performance improvement it makes, but if you've neglected this area defragging your computer can make a huge difference.
Windows comes with a basic defragmentation tool, but for the best results it's a good idea to use a third-party utility such as O&O's Defrag V8 Professional Edition. It offers more flexibility than simple tools, allowing you to defrag a range of computers running different operating systems, and hold huge amounts of data. It can even defrag a PC running Windows NT 4.0 with up to 1.5 terabytes of data. This is way beyond the capacity of most defrag software.
In version 8.0 the whole process is customisable. You can include or exclude certain jobs as and when you want them carried out. You can also set up a schedule so defragging is done at times that suit you.
It also has some nifty features to help you run the software in the most efficient manner. For example if you're using it on a notebook, it will automatically pause when it's unplugged from the mains, so you don't waste power. This version will also run every time the screensaver is activated and then pause once you start working on your PC again.
The Job Assistant helps you keep track of the process, showing you how things are going, while one-button defragging allows for instant automatic defragmentation at the optimal settings for your PC.