How do I add a password to my windows startup?  I use Windows 2000. 
When I loaded it I chose not to use a password.  I would now like to
do so.

Here are instructions at at Annoyances.org

Get Rid of the Logon Screen:
http://www.annoyances.org/exec/show/article04-103

Windows 2000 - solution 1: 

Double-click the Users icon in Control Panel, and choose the Users
tab.
Turn off the Users must enter a user name and password to use this
computer option, and click Ok.
Windows 2000 - solution 2: 

Double-click the System icon in Control Panel, and choose the Network
Identification tab.
Click Network ID and follow the instructions on screen. 

Here is some more information about a TweakUI tool which may be of
interest if the above solutions wasn't helpful:
http://www.pcworld.com/howto/article/0,aid,102523,pg,2,00.asp

Search terms used:
Windows 2000 startup password

The directions were not exactly correct but got me close enough to
figure it out.  Thanks!

Go to Control Panel - Users and click on the "New User..." button.
This takes you to a wizard where you can set your name, password and
other details.

if you want to change the password of the login you are currently
under then all you have to do is to press CTRL+ALT+DEL then select
"change password"... do not enter anything in the current password box
as you do not currently have one... then enter the new password and
confirm and then hit okay.  DONE!  now wasnt that easier.

but if you are creating a new user (which i dont think you are) then
you would want to got to the process of setting up a new user... but
all you wanted to do was change your current password.  CTRL+ALT+DEL
is soooo much easier!  happy computing