How to Remove File Encryption
Encryption is a method of preventing unauthorized access to computer files. When you apply encryption to a file, the file is altered so that it cannot be read by others, unless you have given them an encryption key. Windows XP supports encryption through EFS, the Encrypting File System. If you have encrypted a file on your Windows XP computer, but no longer want or need the file to be encrypted, you can remove file encryption by changing the file's properties in Windows Explorer.
Locate the file from which you want to remove encryption in Windows Explorer.
Right-click on the file, then click the "Properties" link in the context-menu. This opens a Properties window.
Click the "Advanced" button in the attributes section of the Properties window. This opens the Advanced Attributes window.
Click to uncheck the box next to "Encrypt contents to secure data" in the Advanced Attributes window. Click the "OK" button to close the Advanced Attributes window.
Click the "Apply" button in the Properties window, then click the "OK" button. This closes the window and completes the encryption removal process.