Boot form external HD with windows 2003 server

Hi Everyone ,

I recently bought a toshiba satillite A305-s6992e and I am trying to boot with an external hard drive with windows 2003 installed in it.
I changed the boot sequence . Now when it is loading is show windows 2003 loading screen for 1 second and shuts off.

Any help.

Thank you very much in advance.

Sam.

is that os on external harddisk that you used is installed for your current hardware or any other pc because that can be problem of driver conflict ..!