"Looking to sell an old computer and want to wipe the hard drive clean before you sell it? Whatever your reason may be, there are lots of programs out there that can help you to not only erase the data on a hard drive, but erase it in such a way that it can never be recovered again. If you have a lot of sensitive information, perform a secure wipe of your hard drive is highly recommended.
A secure wipe basically performs a low-level format so that the entire disk is overwritten with 0′s. Other software will write junk data multiple times over the disk so that there is no trace of what was there before. Either way, no one is going to be able to get the original data off the hard drive because it’ll be completely gone.
In this post, I’ll mention five fairly popular programs that you can use to really erase a hard disk properly. There are so many good free programs, that it’s really not necessary to spend any money on doing something like wiping a hard drive. You’ll pretty much get the same results using freeware.
While you might not be able to really, truly destroy data (see my past rants about deleting data), you can make it really really hard to recover without spending tons and tons of cash and put your data beyond the normal human's ability to retrieve it. If you're like me and have tons of old HD's laying around that you don't know what's on it, and so can't just trash them, these utilities might come in handy when you get around to nuking them (Note to self: hint... hint... that stack of old HD's in the garage is going to fall over one day and hurt someone...)