Bought a machine (Laptop Used), shop had wiped it clean, installed new OS (XP). Unit worked great for a while, till I needed to try something new. Messed it up, went to Restore function, it also worked great and it was so good that I got my repair and all the Doctors files he assumed were erased or deleted. I worked on that machine for two months and finally got rid of all the files, or so I thought, still find one occasionally now and then. They never go away unless you use a hammer or shotgun. FWIW
"As Pogo said, 'We have met the enemy and he is us' "