Encrypt to Delete
Encrypting files on your hard drive prevents unauthorized access to your information, but you can also use encryption to help ensure that the files you delete aren't recoverable. If you encrypt a file before you delete it, a file-recovery utility may be able to restore the encrypted version of the file, but the utility won't be able to decrypt it. The chances are good that no one else will be able to decrypt them either, especially if you lock the files and throw away the key--the encryption key, that is.
To use Windows XP Pro's built-in encryption, right-click the files or folders you want to encrypt, choose Properties, Advanced, check Encrypt contents to secure data, and click OK (see FIGURE 1
Windows XP creates a unique encryption key automatically if you use this feature. If you wipe out your installation of Windows without backing up the encryption keys, however, and barring some future break in the encryption algorithm, neither you nor anyone else will be able to decrypt those files. So if you choose to encrypt your files this way, you won't need to run a secure erase tool to ensure your privacy: Just blow away the partition, format the drive, and you're done.
Remember to Destroy Your Optical Discs, Too
In addition to erasing hard drives, you need to securely dispose of CDs and DVDs containing sensitive data. Devices such as Aleratec's $50 DVD/CD Shredder and Primera's $130 DS360 Disc Shredder turn your optical media into crumbs. Flash media cards and USB memory keys, fortunately, don't need to be physically destroyed to be wiped clean. If you're worried that someone might attempt to recover files stored on flash memory, fire up the free Eraser block-erasure tool to run a few passes of random data over the drive or card.