How to Encrypt files with Windows XP's built-in encryption
If you have files on your PC that you don't want other window's accounts to be able to access, you can encrypt them. Right click the file that you want to encrypt and select properties from the drop down menu. Once the properties page comes up, choose advanced. Now choose Encrypt contents to secure data and click ok. Now you click on apply. Select encrypt the file only and click ok. Hackers and administrators will not get an access denied message when they try to open the file. To make things simpler you can encrypt a whole folder and everything in that folder will be inaccessible to others. You follow the exact same procedure a you did for the single file, you just start by right clicking the folder instead and then following the previous steps. You will know when a file is encrypted because the text will change color.