沒別的招。Did you install something in between?

A google search (http://groups.google.com/groups?lnk=hpsg&hl=en&q=blank+%22welcome+screen%22+group%3Amicrosoft.public.windowsxp.*) returns quite a few similar reports and you can read by yourself. Seems someone suggested to press Ctrl-Alt-Del twice to get to classic logon screen and type in your account name. But it doesn't always work. Good luck to you.