14 DAY TRIAL // Some people, when selling their old computers will erase everything on their hard drives. This is a pretty good security measure if you don't want others to get a hold of your data. Thing is, this will just prevent some users from accessing your data, and not all of them. The ones that are really tech-savvy can retrieve your data even if it has been deleted. There are even special programs that can do that even if you delete the files from your recycle bin as well. A hard disk has to be wiped using a special software several times, to make it impossible to access the original data on it. That's what brings us to our title. Yes, you can delete something and it will still be there, until that part of the disk where it was originally stored will be properly wiped.
I have to say that I wouldn't have written about this, if I hadn't read this article on The Register. It's about the fact that some group of hospitals had been selling obsolete machines on eBay and that some researchers that got a hold of the hard drives managed to restore data that has been thought to be wiped. So, if they could do it, then so can hackers and malicious users. So, in any case, if you know that you had stored important data on your old PC and now you are willing to sell it, be careful who you sell it to unless you can properly wipe it.
Sure, hackers won't resort to this, to steal info - breaching a database is a lot faster and will offer way more sensitive data than an old machine, but you can never know what the new buyer will come across if he manages to restore the data. In any case, this is not much to worry about, as these things don't happen very often, but I've told you, just so you know.