Today's Internet Web Browsers are designed to make it easy and fast to find previously visited sites. This by necessity leaves tracks that you may not want to leave. To eliminate this "trail" :

Find the "cookies" on your system. For a good explanation of cookies click here.

Deal with the History files kept by your browser:

• Using Microsoft Internet Explorer go to the VIEW or in some versions the TOOLS pull down menu, then to Internet options then General then Clear History. This will clear your History and drop down list of Web addresses recently visited.
• Using Netscape, go to EDIT then Preferences, then Navigator and Clear History