A Win boot disk should be able to delete your primary partition
on your HD, then make a new one with fdisk & format it.
I've seen Win screw up HDs SOOOOO badly that wiping out the
partition is the ONLY WAY TO FIX IT, formatting just won't work.
My friend & I argued about this & one day his PC was like this.
WOULDN'T FORMAT NO MATTER WHAT! A partition wipe did it.
After that & formatting it was back to normal ( Win... normal? ).