If you do not like the Windows 7 login screen, you can change it by trying this simple hack. Here is how you can do it...
First step: Enable customization of logon background
The first step is to make some changes in the Registry. There is namely a loophole that Microsoft has left open for OEM’s to configure customized logon backgrounds.
- Open RegEdit, by typing regedit in the run window.
- Here it could be a good point to make a Backup of the Registry!
- Start a search, by pressing Ctrl + F:
- Make sure you select only Values
- Type: OEMBackground

Once you get the result, which could take some time. You should see this view, which is under HKEY_LOCAL_MACHINE/SOFTWARE/MICROSOFT/:

If you don’t get a result, just create this key, as you see above: OEMBackground as a DWORD 32-bit in the Background section.
Finally to be able to define a new background you need to set this parameter to One (1 - true).

Now you are done with enabling setting a customized background, now you need to create the background.
Step 2: Creating the background in the right folder
The folder for the original background image is (on my machine, change to you system folder and look for oobe): c:\Windows\System32\Oobe\
The original image is the background.bmp, which will be used as a fallback image. To get your own image, you have to follow these steps:
- Create a first new folder: c:\windows\system32\oobe\info
- then another one: c:\windows\system32\oobe\info\backgrounds
- In this folder (backgrounds) you create your image
- Not bigger than: 256K
- Has to be: jpg
- Has to be named: backgroundDefault.jpg
- Resolutions as you want, preferrably as your current screen resolution.
There could be a warning message, but then just click “Continue” when you want to copy your newly created image here.
Now you are good to go, restart your computer and you will have a beautiful new logon screen.