The BSOD has several key requirements:
- Must be clearly different from standard OS operation
- Must work on all hardware. Every video card and every monitor support plain text. Even going back to CGA (Though only VGA and up will support 80x50 text mode).
- The Windows Kernel must be able to invoke it directly, bypassing most layers of the OS entirely, because one of those layers might be the problem. That means no happy shiny windows.
- In plain text mode, there are only 16 colors to choose from, and only 8 of them can be used as a background without special drivers. BSOD must work without any drivers, because drivers are the cause of most BSODs.
Also, if you have a dialog in front, that's not a real BSOD.
As for why it's blue, it stands out.
Aug 20 '10 at 22:26