One of the best ways to keep your personal information and files secure is to use encryption. When you encrypt a file, XP scrambles the contents so that only a person using the account that encrypted the file can read it. Thus, when you encrypt files and then log off your account, only somebody with your account password can read the scrambled documents, making it a good choice for sensitive stuff like financial information, that note to your spouse with the code to your personal safe, and the list of names of everyone you've ever kissed.
This section explains how to encrypt files and folders using Windows XP Pro's built-in tools; the Home edition, unfortunately, doesn't include these features.
Although encryption was once the domain of spies and computer geeks, Windows XP Professional has brought these tools to the masses, making it easy to encrypt files and folders with just a few mouse clicks.
You can only use Windows XP's built-in encryption tools if you have the Professional version and your hard disk uses the NTFS file system (Section 3.3.1). To check your hard disk, right-click the icon for your drive, choose Properties→ General, and look at the File System entry, which indicates whether you have an NTFS file system.
Here's how to use Windows XP Professional's encryption tools:
Right-click the folder or file you want to encrypt and choose Properties→ General→ Advanced.
If no Advanced button ...