Once you've installed a second hard disk, whether it be internal or external, it's a good idea to use it to store a backup of your important documents. If your main hard disk fails at some point in the future, you'll have a safe copy of any vital documents or cherished photos. Storing backup data on an external disk is particularly convenient, as it allows you to quickly copy your files to a new computer. If you stored backups on a second internal hard disk, you would need to replace the broken disk and reinstall Windows in order to access them.

Both Windows XP and Windows Vista include backup utilities, or you can use free utilities such as Cobian Backup. Remember that the more frequently you backup your files, the more you can save should the worst happen.

Adding a second hard disk to your PC is an easy way to extend its usable life. External disks are particularly easy to use, as you need only plug them into a USB but adding an internal hard disk takes only a few minutes and gives you plenty of fast, inexpensive storage space.

Finally, if you come to sell or dispose of an old PC, remember that it's a good idea to remove the hard disk. You can then install it into your new PC or fit it into a caddy and use it as an external hard disk that's ideal for storing backup files.