48. Prevent Computer Users From Logging on to Windows at Certain Times.

If you would like to prevent a member of your household or office from logging into his or her computer at certain times, you can create restrictions on their user account to do this.

To restrict access times for a certain user open the command prompt ('start\run' and type 'cmd'). To restrict a certain user's log in times to Monday - Friday, 5AM to 8PM, type 'net user (username) /time:m-f,5am-8pm

Replace (username) with the required user name. You can change the days using (m,t,w,th,f,s,su) and change times using the same method shown. The user will not be allowed to log in at any other time.

Note that this will not prevent users from using the computer during restricted times if they have already logged in. It only prevents them from booting into Windows.

49. Encrypt Your Important Files (XP Professional)

Windows XP Professional contains a built-in file encryption utility which can make your essential data inaccessible to anyone who does not possess the correct user name and password. Essentially, no one can read the encrypted files except you.

To encrypt your data, right click a file or folder you wish to encrypt and choose 'properties'. Then click the 'advanced' button at the bottom.

Check the 'encrypt contents to secure data' button to encrypt your file or folder. Hit 'ok' to confirm. You'll notice the icon text has changed to green to indicate that the file is encrypted.

If you wish to allow certain other users access to the file or folder, right click the encrypted file again, choose 'properties' and 'advanced' then hit the 'details' button at the bottom of the screen.

Under the 'users who can transparently access this file' heading, use the 'add' button to add any users you want to allow access to.

Note that files and folders are encrypted using a numerical key derived from the unique SID (Security IDentifier) number assigned to each XP user account. This means that you MUST un-encrypt your files if you plan to either delete your user or re-install WindowsXP. Even if you create a new user with the same name and password, they will not be able to access the files.

Only the original creator and users they designate can open encrypted documents.

Windows XP allows the creation of a recovery agent which can transfer the ability to open encrypted files to another user account. For more info on recovery agents and file encryption, grab a coffee and read PCstats Guide to Encryption and Online Privacy.