WindowsXP does not Boot Up/Load... Need advice

Heres what happens when my friend turns on his computer:

Computer starts and normal information is displayed in DOS and then when windows XP supposed to load it says press a key to reboot.

Any advice on this?

 

to begin with have has he just fiited/downloaded any new devices ? we need a bit more history on the machine
has it been tempremental for a while

 

he says he didn't download anything or make any changes to it.
says that he just turned it off in the afternoon, went for a nap, and when woke up he had that problem.

 

ok, i got the PC here.
1. theres no error
2. there are no CDs or Floppies inside.
3. boot sequence starts with the hard-drive.
4. keep on looping "press a key to reboot" so everytime i press the any key it reboots and i am back at the same screen after the initial bios and PC hardware info display.

 

well i just learned that the main drive is the cause.
it doesn't even power up nor is it detected in the bios.

I have installed the drive in my other computer, and seems that its not powering up in here as well.

What are my options here? data recovery center?