How to Clean a Hard Drive. Before you donate or sell your old computer, you will need to clean your hard drive. Deleting files does not actually remove them from your computer. In fact, deleted files will remain on your computer unless they are overwritten. Cleaning your hard drive will ensure that all unneeded and deleted files are erased, including any sensitive data that you do not want other people to see.
Back up any information that you wish to save to a new hard drive or compact disk. Once you clean your old hard drive you will not be able to retrieve any files or data.
Go through your computer and make sure all sensitive information is deleted. You will also want to uninstall unneeded programs.
Search the Internet for software designed to clean your hard drive. Include terms such as "erase," "wipe" and "shred" in your search to return more results. Many of these programs will be available at no cost. A popular program is Eraser.
Download and install the program to your computer.
Run the program to clean your hard drive. The program will overwrite any deleted files multiple times to make sure that they have been erased.
Remove the hard drive from the computer if you are just upgrading your computer and install the new hard drive.
Things You'll Need
Backup drive or CD
Hard Drive cleaner program
If your computer is running Windows, you can use the "Disk Cleanup" tool to clear up space on your hard drive. You will still need to run a hard drive cleaner program to erase the files. You can format your computer hard drive to clean it completely. This will remove the operating system as well.