1.how to remove the microsoft window xp
2.how to make logon id and the bar at the bottom transparent.
You can not with LogonStudioVista, custom style logons for XP need LogonStudioXP.
Try some LogonScreens from LogonStudio Gallery on this Page. LogonStudio XP
Those are for XP version not the Vista/7/XP version.
Make a Wallpaper by yourself (with Transparentity or whatever you want) and make a LogonScreen with LogonStudio.
This will not work, the wall/image used will/must be fully opaque.