How to display some text message in a stand alone XP?

I need to display some text message in a stand alone XP after a user logs in and before the PC initializes.
I tried this by means of both registry files and group policy snap-in. But the problem is that both of them displays the text before the user logs in -irrespective of the user(ie. instantly when we press Ctrl+Alt+Del)that applies for all the users. I know i have made the changes in the computer settings that is why this happens.But the thing is that i need to apply the setting for a specific user,not for the specific PC.The computer is not in any domain. What should i do? Is there any way out? Suggest plz.