Often there is a need on an embedded image to disable all [most of] the screens that have Microsoft branding on them or simply don't comply with the embedded device usage and GUI specs provided. Ideally, we'd want to replace the branding on those screens. This implies to text and graphics used there. However, the way XP OS is implemented (please note - this is changed in Vista!) there is no legal way to replace those screens without messing [hacking] with resources of the Microsoft binaries.
Anyway, there is still one Group policy option exists that is helpful at least to disable some screens. So if you want to disable Boot / Shutdown / Logon / Logoff system status messages (typically shown by Winlogon), just set the following registry entry:
You can pre-set the value in TD (your own component or Extra registry section) or at run time (a command during FBA, RegMigrate undocumented feature of FBA, Run/RunOnce request, Explorer Startup item and etc.).