Just get a DOS boot floppy and fdisk all partitions away, or if DOS fdisk doesn't cut it, use a Linux toolkit such as tomsrtbt. Failing that, get a utilities disk from your hard drive manufacturer and wipe it with that (for instance, Western Digital has a cute li'l utility that writes all zeroes to the drive, effectively wiping out everything.)
Then boot from your e-smith CD and go, go go.