Well I'm still not sure which logon type screen you're talking about cause
you describe the old style logon, with ctrl-alt-del needing to be pushed and
the log on to windows box, but you say it the new xp style. The new xp style
logon screen is full screen, says welcome on the left, and list the user
names on the right.
For the new xp welcome screen logon:
Log into a user, hit the windows key + L, hit print screen key, unlock
station(log back in), open any program that will accept graphics, goto:
edit, paste.
For the old style logon:
Use a program like remote desktop or remote admin, connect to another
computer, when the log in screen comes up, hit print screen key, go back to
your local dektop(but keep the remote connection active), open any program
that will accept graphics, goto: edit, paste.