Deleting a file simply removes its 'address' and makes the space available. The data at that address will be there until it is overwritten. If only part of the data is overwritten, the rest of it will still be there. The government uses software that deletes, writes (usually 1's and 0's), and deletes again, a few times, to ensure that data cannot be retrieved.

Defragmenting will overwrite some of the (deleted) data, as it moves files on the disk. But just figure that whatever you put on your disk will be there for awhile, even if you deleted it, defragged, and added a bunch of new stuff.

Should you worry? Not in any of the circumstances described in the above posts. Uncle Sam is not coming after you for downloading a couple of files that you shouldn't have. If they did that, then most of those illegal videos would not be available for you to download!

For those uninitiated, we're not talking Tracy Lords, (who did X-rated at age 17), but actual [I]child [/I******ography. If you've never seen it, trust me, ignorance is bliss. The makers of this crap are sick criminals who like to be watched (for some, it's part of their motivation). So if you download it, you're rewarding them, while contributing to the continual abuse of the children.

To Hungry Ghosts, above, there's a big difference between thinkin' and doin'. People can steal anything you own, but they can never take your dignity; that is something only you can destroy. Yours seems to be quite intact. Don't be hard on yourself for being curious. Take pride in your self-restraint!