To get back the username and the picture, reverse the above procedure.

 For the New Start Menu, Windows XP looks for the <username>.bmp file in the folder

C:\Documents and Settings\All Users\Application Data\Microsoft\User Account Pictures

If the file is not found, it takes a picture from the "Default Pictures" sub-folder. By renaming the <username>.bmp and the "Default Pictures" folder, you're giving no chance for Windows to fetch an image for the Start Menu

~ Cheers ~.