How to Customize Windows 7 Startup Screens
Changing the default startup screen in Microsoft Windows used to require special software or complicated hacking, but Windows 7 makes the ability much more accessible. After making sure the feature is enabled in the Windows Registry, you can move any JPEG you want into Windows' special "backgrounds" folder and see it appear behind the login prompt at Windows startup. For best results, you should use an image with the same resolution as your monitor.
Click "Start," type "regedit," and press "Enter." This will bring up the Windows Registry Editor, through which you can modify system settings. Registry "keys" appear in the left pane, in a nested folder structure; clicking one of them will bring up "values" in the right pane.
Navigate to the following key in the left pane: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Authentication\LogonUI\Background
Check the right pane for a value named "OEMBackground." If it exists, double click it to edit it, and ensure that it is set to 1. If it doesn't exist, right click in the right pane, point to "New," and click "DWORD value." Name the value "OEMBackground" and double-click it to set it to 1. Close the Registry Editor.
Open Windows Explorer and enter the following path into the address bar:%windir%\system32\oobe\info\backgroundsIf the folder doesn't exist, you can create it yourself. First enter:%windir%\system32\oobeRight click in the folder and select "New Folder." Name your new folder "info," double click on it to enter it, then create another new folder called "backgrounds."
Drag whatever image you want to use for your startup screen into the "backgrounds" folder.
Right click on the file and select "Rename." Name the file "backgroundDefault.jpg". You can also give it a resolution-specific name -- for example, if the file is 1024 by 1280 pixels, you can name it "background1024x1280.jpg." When Windows starts up, it will first check the backgrounds folder for a file with a name corresponding to your monitor's resolution; if it can't find one, it will use "backgroundDefault.jpg" and, if necessary, stretch or squeeze it to fit.
Log out of Windows to see your new startup screen.