If you decide to upgrade to a new computer, because your old computer just isn’t up to the job any more, what’s going to happen to the hard drive from your old computer? One solution is to use a USB flash memory device to copy all the data from the old computer, if it still runs, to the new one. This works, but can take ages if you’re only able to copy a small amount of data at a time. Another solution is to remove the hard drive from your old computer, attach it to your new computer temporarily, copy all your valuable files from the old computer to the new computer, then put the old hard drive in a drawer somewhere and probably forget about it. However, if the old hard drive is in good condition, there’s a better solution, which is to turn it into an external hard disk drive.
For less than £25 you can buy a device called a hard drive enclosure, install the old hard drive into it, and then you’ve got yourself an external hard drive. You can plug the external hard drive into your new computer, copy all your data onto the new computer, then use the external hard drive for backing up your new computer on a regular basis. In this way, for a very reasonable price, you can turn your old hard drive into a useful device instead of simply abandoning it. If the new computer has a lot more storage space than the old one then it won’t be possible to backup everything from the new computer onto the external hard disk drive, but you should always have a strategy for backing up at least your personal files. The operating system can always be reinstalled, and your applications can always be reinstalled, but your own files are far more important, so if there’s only a limited amount of backup space, they are the things to back up.