Windbg --Local Kernel Debugging

You can get more information here..http://msdn.microsoft.com/en-us/library/windows/hardware/ff553382(v=vs.85).aspx

You will see "bcdedit -debug on" error message.  Actually, you can use LiveKD to run windbg to solve this probem.

Difficulties in Performing Local Kernel Debugging

Local kernel debugging is a very delicate operation. Be careful that you do not corrupt or crash the system.

One of the most difficult aspects of local kernel debugging is that the machine state is constantly changing. Memory is paged in and out, the active process constantly changes, and virtual address contexts do not remain constant. However, under these conditions, you can effectively analyze things that change slowly, such as certain device states.

Kernel-mode drivers and the Windows operating system frequently send messages to the kernel debugger by using DbgPrint and related functions. These messages are not automatically displayed during local kernel debugging. You can display them by using the !dbgprint extension.

LiveKD

The LiveKD tool simulates local kernel debugging. This tool creates a "snapshot" dump file of the kernel memory, without actually stopping the kernel while this snapshot is made. (Therefore, the snapshot might not actually show a single instant state of the computer.)

LiveKD is not part of the Debugging Tools for Windows package. You can download LiveKd from the Windows Sysinternals site.

http://technet.microsoft.com/en-us/sysinternals/bb897415.aspx