I dont think its possible, maybe if you have some sort of program (I have never heard of one though)
The thing is if someone gets a hold of your HD, they can see what has been on it for the last 5 years or something (depending on how much you have downloaded/delete I suppose). There are companies that do this for a living.
btw im in no way an expert on the stuff. Why do you ask?
I know that if I found out the police were gonna search my apartment I would remove the HD from the computer.