This is a very simple trick to do if you have done the same for the logon screen and the start button. There are 2 ways to do this trick that I know about one is doing it manually and the other is using a program called bootxp. I am going to tell you the manual way to do it, but if you want to know the other way just let me know, so I can do an update to the guide. Now once you have downloaded your ntoskrnl.exe file save it a general location so that you will have easy access to it, like my folder.
Now that you are there copy the file that you want to change your boot screen too. Once you have copied that file, hit the window key + r or type %windir%\system32 in the run command, so that folder as follows.