download the iso powertoy for your version of windows xp (sp1 or sp2)
Install, reboot.
Download the rc.iso from the link above
Right click it, choose BURN ISO
you will create a cd from the ISO image
reboot with the new cd and see if it will allow a repair option.
If it does, can you see the missing drive?
Also, when your computer first starts, does it detect all the known drives ?