windows xp will NOT boot

Hi, ive been having various problems with the same samsung sata hd!

this time around windows xp will NOT boot at all! i get to screen thats says: start windows normally, last known good config & safe modes.

Ive tried all of these options only o find that the pc just reboots itself to go into this same screen!

so far i have used xp disc to do:
chkdsk /p (which found and repaired error)
fixmbr
fixboot
none of these methods have helped at all!

all i have left to do is reset bios (shorting pins).

But i this doesnt work what should i do???

I bought the hd from pc world and hqave had it replaced 3 times already!

1st time was for this error message i have again. Second time was after it completely died (not found in bios)

amd 64 4000+
a8n32 sli dlx
nvidia 6800gt
amsung 250gd SATa HD

Any help much appreciated!!!

Thanks
Tom