From reading some of the threads here, I see that some people do not really understand that formatting a hard drive and running the so called cleaners that are around, does NOT make the data non retrievable.
There is a program called forensic recovery suite that is used by the USA law enforcement that can totally recover ALL the data on a so called wiped drive. I was given a copy of it, and as a laugh I went and reformatted a drive that I was going to anyway, used a low level format on it zero filled it and used a couple wipe programs on it.
I fired up forensic recovery suite and was able to recover the information on the so called formatted drive.
This is why when a government department or even a business does not sell the hard drive that they were using when they dispose of their computers.
Not all companies do that, but a number of the government departments do.