Firefox ------ Top Sites

I'm running Firefox on Windows 7.

When I start Firefox I am presented with an initial screen listing 'Top Sites' - a screenful of large icons for a number (14 at the moment, but it varies) of web pages I have visited recently, giving easy access to my browsing history. For personnel reasons this is undesirable - it would give ready access to personal, private data that should be confidential.

Is there some way to switch this page 'OFF', or do I have to keep remembering to 'kill' the icons before leaving the computer?

 

Options > Privacy and Security > History > Never Remember History

 

Tools > Options > General > When Firefox starts.
Select either:
Show your home page.
Show a blank page.