So you have a Windows XP system and you don’t feel like getting prompted to login all the time.
Start > Run > control userpasswords2
Select the account you want to use and then uncheck the “Users must enter a username and password to use this computer.”
Also note, you can clear out website cached credentials by going to the Advanced tab > Manage passwords button. Click the Remove button for any entries you want to clear out.
A much more detailed description can be found here: http://wiki.ljackson.us/Control_Userpasswords2