Problem with Debian 4.0 security

[Bret Busby <bret@busby.net>]

Hello.

I am running Debian 4.0 on this computer.

The facility Desktop -> Lock Screen, is not working.

The facility Applications -> Debian -> Screen -> Lock -> KTux, raises a 
screensaver, but that screen can simply be closed, by clicking on the 
cross in the top right corner of the window, and does not require a 
login, to unlock the screen.

The facility Desktop -> Logout -> Switch User, goes to a login screen, 
but then, when the screen is turned off, and, turned back on, some hours 
later, the display is returned to how it was before using that 
facility, without the login scren appearing, and, without logging in.

As, in these circumstances, the computer can apparently, only be 
secured, by shutting it down, a security issue appears apparent.

As the above facilities for locking the screen, do not work properly, is 
there any other reliable way to lock the screen, without losing the log 
in session?

Thank you in anticipation.

--
Bret Busby
Armadale
West Australia
..............

"So once you do know what the question actually is,
 you'll know what the answer means."
- Deep Thought,
  Chapter 28 of Book 1 of
  "The Hitchhiker's Guide to the Galaxy:
  A Trilogy In Four Parts",
  written by Douglas Adams,
  published by Pan Books, 1992

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