as previously discussed, when you delete something from your computer it isn't actually deleted. the cipher.exe utility that is included with windows xp professional provides the ability to overwrite un-allocated space on your hard drive, making data non-recoverable. if you're using home edition, you're pretty much stuck using third party utilities to tackle this project so feel free to skip it if you want.
what we're going to do is create an icon on the desktop, and when you double-click it (or use a key-combination to trigger it) it will delete all of your sensitive data from your computer and make it non-recoverable.
first of all you should have an encrypted folder where you store all of your sensitive data, as having it in one location will simplify things. let's create a folder within our temp folder for this called "secret." assuming you store all the goods here, you can encrypt it by typing the following command the dos prompt: "cipher /e /a c:\temp\secret". although files added to this folder later will be automatically encrypted, we should go ahead and encrypt the existing contents should you have any. type "cipher /e /a c:\temp\secret\*.*" to achieve that. now just make sure that you store all of your secret crap here; in fact, go ahead and throw a few files in there so we can have something to work with.
now, let's make a batch file. open notepad. first thing we want to do is delete (but not really delete) everything out of our secret directory, including the directory itself:
rmdir /s /q c:\temp\secret
then, we want to overwrite (this time really delete) the data, which is still invisibly hanging around. to accomplish this, we'll use the "w" switch. we will specify the folder where our deleted content used to reside:
cipher /w:c:\temp\secret exit
this is pretty easy. go ahead and save the file as "self-destruct.bat" in our temp folder. create a shortcut to your desktop, make a key-trigger if you want to, and change the icon to a padlock or something cool and you're good to go. the only thing to keep in mind is that it's probably a good idea to quit all running programs before launching your self-destruct to achieve the most desirable result, as open programs can still write to the hd.
the following version of our script will close all running programs for you. after all, why do it yourself when we can code it?
we have to instruct taskkill not to close applications we need (exporer.exe & cmd.exe) otherwise this code would pretty much freeze/crash the system. and yes, i found that out the hard way.
disadvantages of cipher compared to other software:
if you're super paranoid i would definitely recommend looking for an alternative; otherwise the cipher.exe utility should do just fine.