I’m considering giving my current computer to a friend when I purchase a new one. I am a bit worried about the existing content on the hard drive. How can I delete the files and other content on this Windows PC so that my friend couldn’t recover any of my information on the hard drive?
Well, if you can’t trust your friend not to steal your content, she’s not much of a friend! Really, just kidding—you should always be aware of the content on your hard drive and who has access to it. In addition, you should be aware of the way Windows deletes files: It doesn’t! When you delete a file, Windows simply marks the file as deleted by changing the first byte of the file content, so Windows knows that you’ve asked it to delete the file. It also releases the space used by the file contents so that future file saves can use the same space on the storage medium (hard drive or solid state drive). The problem lies in the time between when you delete a file and when you reuse the space. You have no way of knowing when a file has been overwritten, and until that time, all its contents are still there, albeit unavailable by normal means (but very available by folks determined to find the content). Normally, this isn’t a problem—it’s your computer, your data, and if it’s still on your hard drive, who cares? (And, in case you need to do so, this means of marking files as deleted makes it possible for file-recovery utilities to do their work. If you have ever needed to recover an accidentally deleted file, you’ll appreciate this!)The problem occurs when you want to give the hard drive, or the entire computer, away. In that case, you want to ensure that your data is, in fact, gone entirely. You could follow the general prescription: Format the hard drive and reinstall the operating system, and this would indeed remove all your files. This process doesn’t guarantee that all your data is completely removed, however. For that, you’ll need to use one of several tools that can securely remove all the data from your drive. You can find many such tools online—search the Web for “securely delete files Windows” or “securely delete files Mac”. The following link includes information about performing this operation, and some tools you can use: http://lifehacker.com/5835369/how-do-i-securely-wipe-a-computer-before-donating-it-to-charity