You always keep important documents under lock and key. Also on your computer several of your files are "for your eyes only". If you want to be sure that other people cannot read your letters or see your photos, you should encrypt them and protect them with a password. There are several software programs that can do this for you.
I am very satisfied with the program Silver Key. After installing it, this program becomes integrated with windows explorer (and other file managers). Just right-click on the file (or folder) that you want to encrypt and give a password. This will immediately create a new encrypted file that can only be opened by entering the same password.
An extra feature is that the encrypted file can be a so called “EXE parcel”. The file will have the extension .EXE and when you click on it, it will prompt for a password and then decrypt automatically if the password is correct. So you don’t need a copy of Silver Key to decrypt a file, you just need to know the password or pass phrase.
Passwords in Silver Key can be very long; you can use a “pass phrase”. Make use of that for extra security. Always use strong passwords.