Repeated reboots

My machine was working perfectly. I have not recently
installed any new drivers or hardware. I shutdown my
machine normally. A few hours later, when i tried to
reboot, i get just past the windows xp splash screen, and
it says "windows did not shut down properly" and then the
list appears- boot in safe mode, safe with network, last
good config, boot normally - and i try every one, and the
machine reboots over and over and over.

Then, I try booting with the windows xp install disk. i
try to reinstall windows xp. but then the thing says
that my disk is either too full, of the wrong partition
type, or faulty, and it wants to reformat the disk. so I
dont let it do that.

Then I reboot with the cd, and try the recovery console.
but the console won't let me do even a dir command on the
c drive - it says error compiling the directory or
something.

I have basically no way of seeing the error message when
booting because of the automatic reboot feature. no
other way of getting this machine up and running is
working. I am really hoping to avoid a reformat. I cant
believe that another hard disk has failed in less than a
year? Surely the hard disk has not failed again? It has
not been acting strangely at all, and the machine has
been working perfectly lately.

Please help! PLease send to my email address listed
above, because im am using my dad computer for this
message.


Thanks

Repeated reboots