Rescue Windows XP Again

My son’s desktop PC crashed on 6 April 2010 and it was restored by fixboot to repair the boot.ini program.  After 14 months, it crashed again.  This time the master boot record was corrupted. The rescue method was to run FIXMBR at the System Recovery Console. 

I wonder why XP boot up process gets into trouble so easily.  Or else the hard disk in question is not so reliable ?