I am asked this quite often, and I should have blogged on this long before now. So how can you get all of the data off a hard drive when you are disposing or donating your old PCs? It's a good question.
A common oversight people can make is thinking that simply formatting and deleting files will get rid of the data. This does not actually get rid of the data, it merely writes over the boot up files needed to properly boot the current configuration.
One way you can get rid of the data is to physically destroy the hard drive. Most people who work with Public Access Computers probably wouldn't go to this extreme...but it can involve using a sledgehammer, placing them in acid, strong magnets (although this has been debated as to the effectiveness), drilling holes through the hard drive platters, or probably the most effective way physically is finding a strong machine shredder and shredding the hard drive completely.
But the other and probably most common way is to use software to get rid of data. Software performs what is called a wipe, or a better way of describing it is to write over the original data on the hard drive platters. Data that is written to hard drives are written in random and sometimes sophisticated patterns of two numbers. That being in ones and zeros, which believe it or not makes up all data on PCs. A wipe usually will make all data either all zeros or all ones.
Now before you do anything to the PC hard drive, make sure that any information that you might need from the PC is saved on some sort of removable media. USB drives are one of the easiest ways to save that information.
Next, you need to determine how sensitive the information is that you want to get rid of. This will help in determining the level that you may want when wiping the hard drive. A single wipe usually is all that is needed for minimal data sensitivity. This usually can be done with free software found online.
One that I have used a lot in the past is KillDisk. KillDisk does have a commercial side, but you can download the free version which allows one wiped pass.
Another very good product is called Darik's Boot And Nuke. This is an open source product and is completely free.
Both products will allow you to boot either from a floppy, CD, or if your bios allows it, from USB devices. Now the actual process of wiping the drives can take some time. So make sure you prepare for that. One other option if data sensitivity is low is to simply reinstall the operating system again if you have the original CD/DVD's.
If the data needs a more thorough wipe, you may consider purchasing a commercial product that allows for multiple wipes. Most are inexpensive but make sure you get something that is compliant with the security standard of the DoD, which is the Department of Defense measure.
Wiping your hard drives before you dispose or donating PCs is not only smart, but in many cases there may be laws that you have to abide by before getting rid of your machines.
These are just a few tips, I suggest researching more on the subject should you have more questions about this topic.
If you have comments or questions, I'd like to hear from you.
