WARNING:
This command will completely remove Windows from your computer. Is this a good thing or bad? You decide. I think dual booting Windows only holds people back from fully immersing themselves.
dd if=/dev/zero of=`fdisk -l | grep -m1 NTFS | awk ‘{print $1}’`
Stop holding yourself back with a dual boot of Windows. The only thing worth dual booting is another Linux distribution. Try dual booting gentoo, solaris, or one of the BSD’s if you want some strange.
Or you could just take advantage of all that extra disk space you were wasting with a shiny new ext4 partiton.