I'm still skeptical. Ursula are you saying that if I store a document with only the letter "a" in it and write over it with random letters other than "a" thousands of time that someone somewhere can tell me what that original letter was?

And that given time and money that person can pull out enough information to determine a file was porn and specifically child porn?

Sorry, don't buy it. Governments with billions of dollars to spend will recycle hard drives after overwriting. With that kind of money incineration would be the avenue of choice.

Please give us a reference to your information.

PS: Most of the returning people I see here are either asking how to get rid of it or telling people how to get rid of it.