2 words.

deleted. isnt.

The only sure fire way I have found to erase info from a hard disk and make it unrecoverable is to totally destroy it. then burn it. then nuke it. then give it to my kid brother for the day. then leave it in a subteranian underground layer in a pool of acid for the day. Then pour moulten lava on it. then throw it under a train. then tell mr t it called him a monkey. then use it to hotwire a car. then have luke sky walker play baseball with it. then allow it to complete the T-Rex feeding cycle. Then spread it with cheese and take it to a comic convention. then tell Saddam it is not his.

Even after all this. There is still a chance.

So in short if it has that picture of you and the wife doing that wheel barrow race thing or has personal financial info etc. Just hit it with a brick and burn the remains.