When you empty the recycled bin to delete some unwanted files, where do they go? I don't see an exhaust pipe on the Hard Drive so there is no way that it escapes through a conduit.

Second question, if you want to sell your old hard drive, and you reformat it and kill say 15 GB of garbage, where does it all go? I have heard people say that the info is STILL there if someone REALLY wants to retrieve it. If your 15 GB of junk is still there, how would the drive show that capacity is about 20 GB?

So really...what happens to the data when it gets deleted? Does it get compressed somewhere else?

Thanks for enlightening me!

So really...what happens to the data when it gets deleted? Does it get compressed somewhere else?
If my understanding is correct, when you deleted a file it's still there but it can't be seen. Windows (or DOS if that's what your operating system is) then designates that space as empty and available for writing other data. Then if you write or install other files in that space, then the file/s that you originally deleted will be gone since that space will be overwritten by the other files. Now--I may not be totally correct on that. There are many members of this forum who are much more knowledgeable than I am. Maybe someone can add to what I said if I'm not totally correct.
~Frank~

The recycle bin is basically just another folder. Yes, it's a system folder with special properties, but when you move a file to the recycle bin you've basically just moved it to another folder. Now, has that data actually moved somewhere on your hard drive? No - you've just told your hard drive to make the association between the file and folder, and remember it as such.

What about deleting data? Start here (http://www.pcguide.com/vb/showthread.php?s=&threadid=8331). Post back if you're still confused. :)

Simply deleting the file on the drive does not erase it...it just says the space is no longer occupied.

It rewrites the pointers (in the FAT) to the file and doesn't do anything to the actual data.

Reformatting is even worse, because all it does is remove the partition table and the FAT and rebuilds them. Rather simple to recover from, as long as no new data has been put on the drive.

To clean a drive you will need to do several passes with a "zero fill" utility, preferrably one that will not only use a single character but several in a random pattern and alternate those passes with a single character.....

This helped a lot. When you wipe a drive clean, you can still use it and treat it as a new drive correct?

Yes, after wiping a hard drive clean, you will need to partition and format it, and it'll be ready to use.

When I want to make sure that a drive is "clean" of all the info I have had on it I run PGP Drive Eraser over it 5 times. This does exactly what MJC said. This ensures that (at least to average user, and, as far as I understand, makes it very difficult for professionals) no info about previous use can be recovered

Freeware versions for all OS's can be got here
http://www.pgpi.org/products/pgp/versions/freeware/

Here (http://www.pcguide.com/vb/showthread.php?s=&threadid=23177) you can find links to a few other utilities to wipe your hard drive.