My mother is a regional director for IBM and the systems administrator for the vast majority of their high dollar corporate accounts. She is literally the only person who can get into the base of IBM's global system dating back to DOS formatting. Short of physically replacing everything, motherboard's, processors, hard drives, etc, she can find it. She can also see what has gone to your IP address. Crazy shit. I'm not sure if you're asking for your protection or just to retrieve some old files, but in this day and age EVERYTHING is retrievable. It just depends on how far they want to go and how talented a person is.