If you want to get rid of Windows' Logon password box:
Go to Start/Find/Files and Folders
After you click on File and Folders, a box opens.
Enter *.pwl as your search term.
Make sure the Look In box refers to C:\ and that the small box below (Include Subfolders) is checked.
When Find finds your pwl file, delete it, by right-clicking on it and choosing Delete from the pop-up menu.
Restart Windows. You'll get a Password box. Enter your name, but do not enter a password. Click ok. If you are asked for a confirmation, click on ok again.
Also try the following:
Go to the Control Panel and there click on the Passwords icon
You will get a Window named Password Properties
Click on the Change Passwords tab (though you may already be in the Change Passwords section by default).
Click on the Change Windows Password button
Click on OK
In the Change Password Window, make sure that the Old Password, new password and Confirm password windows are blank.
Click Ok, then click again ok. Then restart the computer
On restarting, when you see the Enter Windows Password dialog box, just click ok again.
If you still get a password prompt, it may be that there is a second, hidden pwl file on your system. Find it and delete it as well.
One warning: After you do this you will have to re-enter all passwords (for your ISP, for example) you use in the course of your regular computing sessions.