resetting or formatting a disk does not remove the information on it.
It only removes the pointers to the data.
You need to replace the hard drive with a new one or secure erase the drive.
Use one of these tools to completely remove your data.
Otherwise it can easily be recovered after a format or reinstall. https://www.google.com/search?clien...Vph-AKHX1sAQMQ1QIoAHoECA0QAQ&biw=1920&bih=955