This graphic is embedded in the Io.sys file in your root directory, and is easy to change. If you don't want the logo's to appear, you may open "Msdos.sys" (hidden file at C:\) in Notepad. Add or edit the line "Logo=0" under [Options].
Windows stores the splash screen in the file LOGO.SYS. Even though this file has the SYS file extension and is marked as a system file, it's actually a bitmap file created in Paint. This means that basically all you have to do to replace the Windows splash screen is create a new bitmap and save it as LOGO.SYS.
Before you begin, you should rename the existing LOGO.SYS file so you have a back-up copy of the original splash screen. Since LOGO.SYS is a system file, Windows Explorer and My Computer consider it a hidden file, even though the hidden file attribute isn't set. Therefore, neither of these hard disk navigation tools will display LOGO.SYS unless you change the View option to show hidden files.