here s the video tutorial
http://www.youtube.com/watch?v=CyfSTwPo6hg&feature=related
1. First you will have to download the registry file from the link below
http://www.intowindows.com/wp-content/uploads/My%20uploaded%20files/Enable%20...
2.Then double click the file to enable the features
3.Go to C:\Windows\System32\oobe
4.now create a folder there and name it as Info, then create another folder inside the info folder and name it as Background
5.Now select the picture you want to put as the log-on screen (it should be under 256kb) copy it and paste it in the background folder and rename it as backgroundDefault .
6.Now reboot your pc and the changes must happened if not the picture is not less than 256kb.
