Everyone has private and confidential texts in their PCs. Logically you probably don`t want anyone else to read them. So what you need is a free tool like dsCrypt.
dsCrypt is a utility that lets you encrypt and de-encrypt those really private documents. The most outstanding thing is its ease of use, and it doesn`t even need installation. You just have to select the text to encrypt, place a password and it will automatically be coded. Thus it will be totally illegible to anyone without the password.
To read it again just insert the password and the original file will be decoded.