dd command to clear start of harddrive

[Nigel Henry]

This is not directly Fedora related.

I connect to the Internet through my Smoothwall, and a serial modem. Recently 
the machine that the Smoothwall is running on has been playing up. Harddrive 
spinning up and down. I have another older machine (1.33GHz, 64MB RAM, and 
6GB harddrive) which had Win 2000 pro on it, and was trying to install a 
backup Smoothwall on it. The Smoothwall installs ok, and lilo is installed, 
but when I reboot the BIOS does the memory check, and all I get next is half 
a screenfull of "40's" printed out. they remain for a few seconds, then I 
just get a prompt that I can't do anything with.

I am wondering if something has been left behind on the harddrive from the Win 
2000 install, that linux has not been able to remove.

I've seen a few times a dd command that can get rid of stuff at the start of a 
drive, but stupidly have not written down the info.

Could someone kindly give the required dd command to make sure that the 
harddrive is clear of all data.

The machine won't boot off cd, but using smart boot manager on a floppy, I can 
get Finnix booted up on it, and work off the CLI.

Thanks for any help from the list.

Nigel.