can somebody give a logical explaination to this????????????

im french excuz my english.....
the other day my mpc froze when i was listening a cd ...switch off switch on ...same shit!!!! switch off switch on ...once again it freezes... i format the hard disk because i have read somewhere that a defective disk could be the cause of the probleme... switch off switch on ...then no freeze anymore but the mpc doesnt recognize the hard disk anymore !!!
ok ...i stay 3 days with the machine off ...switch it on again and then miracle !!! it recognize the hard disk again!!! great!!!
i do a beat and after 3hours the machine make a weird sound and freezes again ...switch off switch on ...no freeze anymore but this time it doesnt recognize the hard disk and the cd driver!!!!! WTF????? today i tried to update the OS ... i already have the 1.71 but i reloaded it in the machine just to see if something good could happen but nothing happened... can somebody tell me something
thanks

replace the hard drive.
It is dying, and confusing the cd drive,
or possibly replace both drives. they are inexpensive, and this action will fix your problem

thanks!