If my inerpretation of his query is right then I think he means to change the windows XP welcome screen (where there is an icon for every user n guest which you have to click on to enter the pwd in order to login to windows) to the classic win nt/2k login screen(where you have to insert the username and the password).
If that is it then..
Login with administrative priviledges.
Go to the user accounts menu in control panel.
Here select change/edit a user account.
Here you will find an option somewhat like "Change the way users login"
Here disable the welcome screen.
But remember one thing after reverting to the classic logon screen you wont be able to use the
Fast user switching facility of windows XP.
Hey Ashisharya,
If this is not what u meant then sorry for wasting ur time.
Style XP which Saroman has reccomended is a very good application to modify features n skins of various windows n dialog boxes etc.
I think its freeware.
Go for it.
oh well u aske something abt registry. i have nt done it before so i can just give some hints which may be of some help.
it has to be somewhere in "current USERS" tab. concepts involved is just it changes 2 background images, one the entire bg n second the bg of logon box. i ll get back if i find a precide soln.