If you can boot up in xp so nothing wrong on ram module or fan.
About sound, by deafaults windows server 2003 sound is turned off on service console.
you have to go to service console and enable the windows audio service.

about booting in server 2003 mode,

do you get any error message while booting or its just blank

change the boot sequence on boot.ini file and make windows server 2003 first boot option