Change the setting for your Screensaver.
Select any area of your desktop, and right-click;
on the Display Properties sheet, select the "Screen Saver" tab;
For WinXP you will see the:
"On resume, display Welcome screen", uncheck it.
Note: for other versions of Windows you may see some other sort of selection, something like:
on resume require password, or
Password required, something like that;
just uncheck that, whatever it is called.
(Depending upon the wording you might have to check it, instead, ... whatever)
Then click the [OK] button. That should do it.
After you have initially logged in and have applications running, but have gotten busy doing other things (non-computer items), I get a login into which I must enter my password to get back to my desktop. How do I stop this or have it automatically clear back to the desktop when I move the mouse?