Well first you need to understand that you cannot get rid of the information.
Unless you overwrite it repeatedly or degauss it.

If your not worried about someone who knows what they are doing getting your info
then the easiest way .... is just reformat it. - that just gets rid of what the average person
will be able to access. Anybody with some time and knowledge can get most of your info
back. Including recompiling software.

Overwriting the drive is dodgy. Lots of software claims to do it ... but they don't really.

[DELETED]

Ken is right. WIndows doesn't provide any ability to wipe your system. If you ran it by mistake, it would be a DISASTER! You have to, ironically, buy one, or maybe find a free program.

What I would do, is:

1. Research such programs.
2. Buy a good one that does multiple patterned writes to your drive.
3. Delete all files you want to get rid of. The program may even have a special wipe routine to replace delete. If so, use the wipe routine.
4. Have it wipe all file types you want to get rid of, outside of the windows system area,
5. Have it wipe all unallocated space.
6. Do a defrag. Defrags will wipe out SOME deallocated space, and scramble blocks, making reconstruction of fragmented large documents more difficult, etc.... AGAIN though, defrags ability to do this ranges from the best possible to nothing at all, so it should be used last, etc....

You COULD do the simple delete, and resell, that many do, but recovering files on such a system is very easy. You COULD do a delete, defrag, and resell, but that can be simple also. A multi patterned wipe is NEAR impossible to read. One layer should make any standard attempts impossible. It is rumored that the FBI has a way to go deeper, and maybe 3 layers should make even THAT near impossible. It would take YOU a LOT longer to do though. Nobody would even ATTEMPT to break that unless you were FILTHY rich, or a major criminal.

BTW realize that windows has a TON of flaws. It has logs, "vm", and tends to write in random areas or system areas. So using ANY software on windows to do this won't be perfect.

Steve

Remove the hard drive? That is the only safe way.