Our Helproom Editor explains how to password-protect files when using a PC or laptop running Windows XP.

QUESTION I'm running Windows XP on my computer. I wish to password-protect some of my documents, but I can't find how to do so in the help files. Can you give me some guidance?

HELPROOM ANSWER How you achieve this will depend on which version of Windows XP you're using. If you're running Windows XP Professional then you can use the built-in file-encryption function. Be aware, though, that this is designed to protect your files from access by other users' accounts on the system. If all users are signing in under the same account, this method won't afford any protection.

In Windows Explorer, right-click the file or folder you want to protect and select Properties. Now click on Advanced and select ‘Encrypt contents to secure data'.

Windows XP Home doesn't have this option by default, but you can enable it with the TweakUI utility, available from Microsoft.

In TweakUI, go to the Explorer section and select ‘Show Encrypt on context menu' to enable the Encrypt function.

In Windows XP Home, you can right-click the folder you want to encrypt, select Properties, choose the Sharing tab, and click ‘Make this folder private'.

This option works only for folders in your personal folder (C:\Documents and Settings\[Your user name]\ where C is the drive containing the Windows system). You can read more about encrypting files in Windows XP at http://support.microsoft.com/kb/307877.

Note that these methods require you to be using the NTFS file system rather than FAT32, and that decryption is tied to an Encrypting File System (EFS) certificate stored elsewhere in the system. If these keys become lost or deleted, you won't be able to access your encrypted files. To back up your EFS certificate, you can follow the instructions given at http://windows.microsoft.com/en-GB/windows-vista/Back-up-Encrypting-File-System-EFS-certificate.

To password-protect individual files in such a way that even the file owner must enter a password to access them, you will require some third-party encryption software, of which numerous examples are available.

Depending on the types of files you wish to encrypt, you may like to use a simple compression utility to compress your folder and apply to it a password. A good example of this is WinRAR. If it's textual data you wish to protect, you could save it in a format such as Microsoft Word, which supports its own password protection.

Taking Word as an example, you could paste your information into a document and then save it with password-protection enabled. The exact steps may vary depending on what version you're using; typically, you should select Save As, then click the Tools option in the resulting dialog box. Next, choose General options, and you'll find an option that will let you specify a password that will be required to read the file. Optionally, a password can also be required to make changes to the file.

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