This might be tricky without booting to a cd...

Before you can do anything, I have to know that you can boot to a floppy or an xp setup disk

Try The following:

(1) Try booting to a win98 startup disk, which can be found in the download section I think. If not, you can it google it.
(2) Access the bios and remove the HD(s) from the boot order and try booting to the xp setup disk (CD)


If you can boot to a floppy, but not to a CD, i will give you detailed instructions to boot to the floppy and use fdisk to remove partition(s) and then use the dos prompt to start the 16 bit installer on the setup cd.

If you can't boot to either, then you just might out of luck.
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One more thing. I thought one more thing that you can do. (and it just might fix your problem)
(1) Run chkdsk - either from the dos prompt after booting to a floppy, or from xp, on a secondary computer.