Faulty System Shut Down - Windows XP

My system shuts down on its own for a reason that I need help from you folks.

This is the message on the screen:-

....
"kernel_stack_inpage_error"
disable bios memory options
...
beginning dump of physical memory

After this, the hard disk cannot be detected. I even have difficulty booting up from CD-ROM with a Windows XP to make a repair to the hard disk.

I somehow managed to make the hard disk work again by trial and error. Very confused as to what should be the correct procedure to handle a problem like this.

Please tell me what is the most likely cause of a fault like this to start with, and then describe in detail the procedure to bring back to life a hard disk which is not detectable any more on boot up.

I shall be most grateful if someone can throw some light on this.

Thanks a lot in advance for any help.

JY from HK SAR