To Change the OEM Logo BMP that is displayed when you go to System Properties (Winkey + Pause), Simply find a BMP you wish to use and name it OEMLOGO.BMP. Then go to Start, Run and enter:
%SYSTEMROOT%\System32
Then Copy and Paste the BMP into this folder and it will then be displayed as your OEM logo.
%SYSTEMROOT%\System32
Then Copy and Paste the BMP into this folder and it will then be displayed as your OEM logo.