Microsoft Knowledge Base Article 816307 contains the following summary:
This article describes the best practices for using dynamic disks on Windows Server 2003-based computers.
If you use dynamic disks,
you can create fau...
The subject behavior is likely a computer BIOS problem.
Your BIOS may be set to Stay Off or Last State.
NOTE: The actual names in the BIOS will vary by manufacturer and language.
If the BIOS setting is...