One of my services is setting up new computers and transferring files and settings from your old computer. I usually take the hard drive out of the old computer and temporarily connect it to the new one and then copy the files to a folder on the new computer’s desktop.
The hard drive in your computer holds all your data you create, the operating system, and the program files. An example of data you create would be pictures, videos, accounting databases like Quickbooks and business letters. Examples of operating systems are Microsoft Windows 7 or Linux Mint. Program files would be word processors, web browsers and media players.
After the computer setup process is done, I suggest the owner keep the hard drive from their old computer in case we missed a file or folder during the setup. But the main reason is so unauthorized people don’t get your files. Put it in a static-proof bag and lock in a secure place. If you are getting rid of the old computer, then you won’t have to worry about your data falling into the wrong hands.