Changing my background, prior to login

Hello all. Just wondering how I can change the background you see, prior to logging in. For instance, I had a program running that would dynamically update everytime I logged in, speicifying my reboot time, CPU type, the domain I'm logged onto etc. I chose to remove the exe from my startup folder. Now, the data that was being displayed on my desktop, is now being displayed in the background when I log off, albiet it's not dynamically updating. So it's a stored image. Any ideas??? Thanks