Don't save your logon information 

Always log out of websites by clicking "log out" on the site. It's not enough to simply close the browser window or type in another address. 

Many programs (especially social networking websites, web mail, and instant messenger programs) include automatic login features that will save your user name and password. Disable this option so no one can log in as you. 

Don't leave the computer unattended with sensitive information on the screen 

If you have to leave the public computer, log out of all programs and close all windows that might display sensitive information. 

Don't enter sensitive information into a public computer 

These measures provide some protection against casual hackers who use a public computer after you have. But keep in mind that an industrious thief might have installed sophisticated software on the public computer that records every keystroke and then emails that information back to the thief. Then it doesn't matter if you haven't saved your information or if you've erased your tracks. They still have access to this information. If you really want to be safe, avoid typing your credit card number or any other financial or otherwise sensitive information into any public computer.